New To Spas - Water Chemistry Hurts My Brain!

[arobbert]

There is a formula you can use to determine the amount of chlorine needed post soak.

Assuming a base level of 1 ppm add 7 ppm per person per hour.

This will allow you to adjust your chlorine based on daily use. It is a rough formula. You will need to tweak it based on your own experience and situation (non bathers etc.). The idea is you add just enough chlorine to oxidize bather waste and end up with a little residual for the next day to disinfect . By the next day the chlorine level should be about 1 or 2 ppm. Enough to keep bacteria and algae at bay (assuming your CYA is about 30). if you have more than two people for a soak you may want to raise the starting ppm by 1 ppm per person (assuming you already have 1 or 2 ppm).You will want to test before each soak and in the morning post soak until you get your routine in place. The morning test will tell you if you added enough chlorine the previous night. Once you get this dialed in you can test once a day in the late afternoon or early evening. You to give it a quick bump to increase the chlorine to 1 ppm (or more depending on the number of users expected) if needed. This system will allow you to use the least amount of chlorine necessary for your use. As an alternative you can just maintain higher daily levels of 5 or 6 ppm (or more for more users).

[LydiaRobinvale]

Thanks again for all your help.

 

 I'm afraid we may now have black algae. I am SO FRUSTRATED. It started after the handyman was cutting down a very large tree next to the spa.  Some of the sawdust got in there... Some little dots appeared on the bottom at the far end of the spa. We thought it was just sap from the tree stuff but it seems to have gotten worse like more dots.

They are small black and brown dots and theyre hard to remove. I did try to get one with my finger that was closer to the surface and it smeared a little but there was still a hard spot left.

What can i do jow? I seem to have mostly got the sanitizer thing down but is it too late? I looked at the filter and it has no spots. Is black algae really impossible to remove?

 

[arobbert]

Don't panic. This is not a big problem. What is your chlorine level? 

Do you have your test kit yet? If yes post your results.

If your water goes south just drain and refill. Not a big deal for a hot tub.

[arobbert]

Saw dust would introduce a bunch of material that needs to be oxidized.

Do you have a cover? You should have one. It will reduce your maintenance a lot.

Did you check and clean the filters?

[LydiaRobinvale]

isnt black algae like thr hardest to get rid of and it roots down into your tub??? 

I just shocked it last night. The test kit should be here tomorrow. The chlorine seemed high still today. The filters dont seem to be sucking up grit from the bottom of the spa. I have to constantly use the spa vac i bought. I think its the nature 2 stick i put in blocking flow but there are 2 other filters aside from that. 

I brushed the spots off for the most part. Some of them were really really hard to get off and i wanted to be careful what i used. There are still a few tiny dots in there. The pool has mustard algae right now (i have given up on the pool as the landlord thinks algae is normal and all pools and spas have it) and i don't want cross contamination but i cant prevent what he does.

I dont know how this spa would have got black algae. Can you even kill the roots? Can you tell i am actually panicking? Lol

[MPurcell]

I think mustard algae is the hardest to get rid of, but you can remove any algae. If you do have algae, follow the SLAM - Shock Level and Maintain method from Trouble Free Pool. This is written for pools, but it will work for your spa. Follow the instructions exactly. The only difference I would suggest is to let the water cool down during the SLAM process.

Edit: I re-read over your posts. Based on the description of the one spot you could reach, I'm not convinced it is algae. But whether it is or isn't, how much would it cost to refill? It's only 1,600 gallons. If you drain, you can go in the tub and clean the surface with whatever products needed, including full strength bleach if needed.

If you clean the tub, refill, balance the water, sanitize with chlorine, and never let the chlorine fall below the recommend minimum level for the CYA level, then you will never get algae.

[LydiaRobinvale]

Ok sounds good. I dont think the test kit i got has the kind of free chlorine test that the link you provided mentions, though.

I have ozone though. The test says a loss of 1 ppm fc as a test to see if you're done with the cleansing but it is my understanding that ozone eats up chlorine faster so will i ever get to that point?

You mentioned letting it cool down, meaning turn the temp down? To what exactly? I have it at 100 degrees right now. I dont really want to use bleach. Liquid chlorine seems like the best way to go. I am getting ready to clean the filters but i will wait to soak them until after this process 

[MPurcell]

You must turn off the ozone generator during the SLAM and the overnight chlorine loss test, but the circulating pump should run continuously.

Let the water cool down to ambient temperature. 100 degree water will use up more chlorine during the SLAM.

There is *no* *difference* in chemical formula between bleach and liquid chlorine. Just go to the store and look at the ingredient list on each.

[MPurcell]

The LaMotte ColorQ Pro 7 with it's digital meter uses a DPD chlorine test. (I had to look it up, as not familiar with that test kit.) The digital meter is more accurate than your eyes to get the exact reading from the color, but the problem is that the test itself is only approximate, and more importantly, it only goes up to 10 ppm chlorine so does not read accurately enough to do the SLAM, which with CYA will probably be at 12 ppm or 16 ppm. You can get combined chlorine by subtracting FC from TC. But to effectively kill algae, you need the FAS-DPD titration test for free chlorine and combined chlorine so that you can keep the FC level up continuously during the SLAM.

The recommended kits are the TFTestKits TF-100 or TF-100 XL, or the Taylor K-2006 or K-2006 C, for which the best online price I have found is at Amato Industries.

[LydiaRobinvale]

Like this one?

https://www.amatoind.com/taylor-test-kit-k-2006-c-2-oz-bottles?search=Taylor&page=5

do i need to purchase anything else aside from this?

 

[MPurcell]

Yes, that's the one. The C is for commercial. The price is a little higher because the reagent bottles are bigger, 2 oz vs 3/4 oz in the smaller kit. Reagents are guaranteed good for 1 year by Taylor, but usually stay good for up to two years if they are stored in a climate controlled environment away from other chemicals, ie. inside an air conditioned home in a dark cabinet.

You may find the SpeedStir tool to be of very great value. It simplifies the testing process, and is fun to boot. If you don't have it you wind up swirling the reagent bottle by hand while you add drops with the other hand, which can be a little tricky.

[LydiaRobinvale]

Hmmm my spa doesnt seem to have a way to turn off the ozone...

[arobbert]

Spas don't allow you to turn off the Ozone. This won't be a problem. What is your CC level? This will tell you if you need to shock.

[LydiaRobinvale]

I cleaned the stains off and they havent come back. Perhaps crisis averted?

The test kit came yesterday. The problem is we also went to leslies for a water test. The results were essentially completely different. I am blanking the unit correctly, i believe. The results are as follows.:

Free Chlorine: leslies, 3/lamotte colorq 1.5

Total chlorine: leslies, 3/colorq 3 (no one has been in the spa for over a week and definitely not last night)

Ph: leslies 7/colorq 7.2 (after adding a bunch of ph up last night)

Alkalinity: leslies 70/ colorq 58 (also after adding the ph/alkalinity up. I dont know why i cant keep my ph and alkalinity up and stable)

calcium hardness: leslies 150/ colorq 66 (wtf????)

cya: leslies 30/colorq 43 ugh...

What could i be doing wrong? I dont want to add too much calcium. The guy at the store keeps telling my not to use bleach because it "has other chemicals in it besides chlorine"

i thought this test kit would make things easier not more confusing lok 

[MPurcell]

Quote

I cleaned the stains off and they haven't come back. Perhaps crisis averted?

Let's hope it was just some by-product of the tree being cut down near by.

Quote

The test kit came yesterday. The problem is we also went to leslies for a water test. The results were essentially completely different. I am blanking the unit correctly, i believe.

What could I be doing wrong? I don't want to add too much calcium. The guy at the store keeps telling my not to use bleach because it "has other chemicals in it besides chlorine"

I thought this test kit would make things easier not more confusing lol 

I've already addressed this, I believe. The reason a "good" test kit is recommended is because pool store results and test strips are almost always unreliable. Now does the LaMotte ColorQ digital reader system qualify as a "good" test kit? Probably not, but I think you could rely on the LaMotte test kit results before you could rely on the pool store test results. Thousands of pool and spa owners have proven over and over that a "good" test kit is essential to follow the procedures given on this forum and the Trouble Free Pool forum.

I've also addressed this: The guy at the pool store is giving you false information about bleach. If you don't want to believe me, that's your choice, but before you choose to believe him, please do some independent research on your own. Also ask yourself which one of us stands to benefit financially from the answer given.

I don't know how the ColorQ checks for calcium, but the accurate test, the one you can rely on, is the Taylor titration test for calcium hardness, which is contained along with the other tests in the K-2006.

[LydiaRobinvale]

I think he just believes that all bleach in a regular store has all kinds of other stuff in it. Its odd though because i added half a bottle of the spa calcium hardener and it only went from 50 to 66? That didnt make sense to me. After i added the first half it went up past 75 and then to 150 at the store test.

I also have a taylor kit coming. I didnt want to cross contaminate with the pool as the pool has mustard algae in it right now, plus this only gpes tp 10ppm fc as was mentioned. Maybe i will use this one for the pool and the taylor kit for the spa.

I am keeping an eye on the end of the spa that the spots were on. The landlord turned the spa up to 104 which is the max it goes and i know that will go through chemicals faster.

[LydiaRobinvale]

I tested this morning. Last night i added some MPS to try and free up some chlorine. This morning my FC is about 2 and the total says 6??? What the heck lol.. Is the mps showing up as total chlorine? I know chlorine gives false high mps readings but i wasnt sure if it was the other way around. (Edit to add: i answered my own question and now see mps shows up as combined chlorine for a few days after adding) I removed the Nature 2 stick.. I have a whole tub of leslies fresh n clear though that i would like to use up but its making my ph and alkalinity go down i think.

Ph today is 6.9 and alkalinity is at 62. I added 3 tablespoons of baking soda yesterday. Someone mentioned that fiberglass tubs make the ph go down by itself as well. I am interested to see what the difference will be in readings when i get the taylor kit. The calcium hardness has the biggest difference between the store and lamotte test kit. My research today so far suggests that the calcium hardness test on this kit is not very accurate so i will wait until i get the taylor kit to start worrying.

Should i just ditch the fresh n clear? I only have dichlor at the moment... I have to go buy some bleach. I am going to try it and see what happens. How should i oxidize bather waste after using the tub? Most people say a certain amount per person per hour but thats for very small tubs. What formula would you recommend with a tub this size? I'm sorry this thread is so long, but I'm learning. 

 

[MPurcell]

Personally, I would not throw the MPS away, nor would I use it every day. The biggest thing about MPS is that it adds sulfates to the water which build up over time, and create a bit of a negative environment for the equipment. You already learned about it interfering with the CC test. There may be situations where you want to use it occasionally, though. For instance, you can use it during a soak when you have bathers in the tub. For daily use, use bleach to oxidize bather waste. The amount of bleach you need to add after a soak is independent of the size of the tub. The rule of thumb is approximately 7 ppm of chlorine for each person hour at 104 degrees. At 100 degrees, the number will be significantly lower. You can arrive at a number for your tub by trial and error and testing daily for a while.

If you haven't done so already, read the sticky thread about chlorine demand. The general idea is to add enough chlorine each day to exactly replace the chlorine demand of the tub, and then also add enough chlorine after each soak to exactly oxidize bather waste.

 

[LydiaRobinvale]

I am at walmart now. Their regular concentrated bleach is 6% and says 94% "other ingredients". What are the other ingredients? And if they arent just water, why would i want those other ingredients in my hot tub?

The 7ppm per person hour is for a smaller tub though isnt it? My tub is 1620 gallons...

[MPurcell]

Buy the Great Value brand "concentrated" bleach. It is 8.25%. There is a small amount of, I believe it is lye, which helps keep the sodium hypochlorite from degrading too fast. Liquid chlorine in the pool section or from the pool store will also have a little lye. The other ingredients are water, and any traces of substances from manufacturing.

I don't understand your bias against bleach.

It doesn't matter how large or small the body of water is. One person produces X amount of bather waste - sweat, urea, cosmetics, deodorants, etc., etc. Therefore, it takes X amount of chlorine to oxidize and remove that bather waste. The size of your tub will have an effect on chlorine demand, but not on bather waste.

[LydiaRobinvale]

Ok. Well my bias is that i have never been told to use it and have in fact been told by every single person not to do so, so its going to take a little getting used to. I am not adverse to using it, i am just concerned of the effect on a fiberglass tub. 

As it is not my hot tub i want to avoid damaging it, so i am hust trying to be extra careful. 

Upon inspection when i got home, all those little black dots are back. It is mostly a very heavy black grit. Now i did some searching and found this link here

https://terrylove.com/forums/index.php?threads/black-particles-in-bath-hot-water-only.49345/

Where one guy asks if the black grit leaves a trail when smushed.. That is exactly what it does. He mentions it xould be magnesium sulfide something about the heater element. Now i know they are talking about regular plumbing here (hot water) but i am assuming it could also be trye for a hot tub. Any ideas? 

[arobbert]

If you don't want to use "bleach" you can go to a home improvement or pool store and get Pool Shock Liquid Chlorinator. It is 12.5% chlorine. All chlorine has "other" ingredients. They are part of the manufacturing process and are mostly water, salt and other items used for the manufacturing process. just avoid scented or non splash products. Google "what is chlorine made of" to learn more.

Unfortunately there is no way to get away from chemicals in spa water, unless you want to risk problems with sanitation and or change the water frequently. It took a while for me to accept this.  Many people think salt water systems are chlorine free when in reality they are just another way to produce chlorine. "Non Chlorine Shock" or MPS which is What Nature 2 recommends is made by DuPont and is a chemical compound just like bleach is. Nature 2 recommends you maintain relatively high levels of MPS at all times. They even suggest you test for it before every use. All of the "chlorine free" systems recommend using MPS or Dichlor as a shock to correct incomplete sanitation and oxidization by their products. I have come to the conclusion that they rely on chlorine or MPS to work and do little to reduce the need for chlorine. It makes more sense to me to just use a small amount of chlorine continually instead of shocking with higher doses weekly or when problems arise. Since I switched to the dicchlor/bleach process I seldom have issues with water clarity.

[LydiaRobinvale]

The only thing i was really worried about was that some were saying bleach deteriorates gaskets and such. Since i already have black stuff coming from somewhere and a pump making a lot of noise, i wasnt excited about that. I unfortunately didnt see that last response in time so i did get the 6% walmart brand bleach and not the 8.. I will use the pool calculator to figure out how much i will need.

I did do a recommended experiment on another forum. I gathered some of the black grit (which was very difficult lol) and put some bleach in a small white cup. I waited one hour and the grit was still there, it did not get any lighter or . So its not organic.. I guess. Really not sure what it could be!

[arobbert]

That bleach will work fine.

I don't know what the black stuff could be. How often does it appear? Do you cover the tub when it's not in use? It could be coming from somewhere in the environment. It's also possible it could be related to the pump noise. You should address the pump while it's under warranty.

[MPurcell]

Sodium hypochlorite solution contains both sodium hypochlorite and ionic chlorine in solution. The ionic chlorine will off-gas as chlorine gas, reducing the percentage of sodium hypochlorite in the solution. At any given pH, there will be a balance between ionic chlorine and sodium hypochlorite. Acidic conditions favor a greater amount of ionic chlorine, and alkaline conditions favor a greater amount of sodium hypochlorite. For this reason, there is a small amount of lye (sodium hydroxide) in the solution to keep the pH around 12. This helps extend the shelf life of the product. According to the Clorox company, there is also a small amount of sodium carbonate (washing soda), presumably from the manufacturing process. The rest is water. There is no salt. However, when sodium hypochlorite oxidizes organic matter it produces oxygen and sodium chloride (table salt) so there's nothing there to damage your tub or equipment.

Bleach degrades rather quickly. This is why, when you purchase it for pool or spa use, it is best to get freshly made product, and not store it for a long time. For this purpose, manufacturers often put a manufacturing date on the bottle. The Great Value concentrated bleach has a date stamp on the edge of the bottom rim of the bottle. My current bottle has: 17 116 00:15 S1 GA-01. The first part of the date code means 116th day of 2017, so my current bottle was manufactured on the 26th of April. It's starting to get a little old, but it is only a half gallon and I use so little every day that it lasts a long time.