Help - Low Ph, High Alk! Borax? Baking Soda? Bleach?

[GoobyGirl]

Can someone tell me what I need to do? The following is the water test from Tuesday:

Saturation Index: -0.37 Balanced

Total dissolved solids: 0 balanced

Total chlorine 5.0

Free chlorine 3.7

Combined chlorine 1.3

pH 7.0

Adjusted Alkalinity 133

Total Alk 151

Calcuim Hardness 233

Cyanuric acid 81

Iron 0 Vial turned soft pink, but they said it must be so small of an amount that it turned the water but not enough to register.

Coper 0

Should I add Borax? Bleach? Baking Soda? If so, which one and how much?

I have an 18 x 48 Intex AG Metal Frame Pool w/ vinyl liner. Water is a cloudy light green. I have well water.

Thanks for any help you can give!

Goobygirl

[chem geek]

Your pool water volume for your 18' diameter, 48" deep round pool is 3.14*(18/2)^2*(48/12) = 1018 cubic feet = 7615 gallons so let's call it 7600 gallons.

You want to raise the pH without raising the Total Alkalinity. The only way to do that is with aeration so if you have any aeration features such as waterfalls, spillovers, fountains, showers then you should turn those on. Hooking up a pool cover pump to a shower also works or using an air compressor/pump with a nozzle or pipe to produce lots of tiny bubbles and putting that end into the deep end of the pool works really well.

If you can't aerate the pool, then using Borax would be the next best thing since it won't raise the TA by too much. You would need 5.6 pounds (90 ounces weight) of 20 Mule Team Borax which is about 1.2 boxes (since each box is 76 ounces weight and you need 90). It's probably about 11 cups in volume assuming one box is around 9 cups in volume. This amount of Borax will raise the pH to 7.5 and the TA to 174. So you can see why aeration would be better since it won't raise the TA at all.

Baking Soda is used to raise the TA and only raises the pH a small amount so you definitely do not want to add that.

Your Cyanuric Acid (CYA) level is high and your Free Chlorine (FC) level is too low. You need to target an FC level of 11.5% of your CYA level, so in your case that's 9.3 ppm and should never let the chlorine drop below the minimum of 7.5% of the CYA level or 6.1 ppm. Your current FC is below that which is why you now have algae. You also have Combined Chlorine (CC) = 5.0 - 3.7 = 1.3 ppm. You will need to seriously shock your pool with chlorine, but since your CYA is high it will take a huge amount of chlorine so rather than go that route I suggest you just mini-shock by adding 20 cups of 6% unscented bleach (Clorox Regular or off-brand Ultra) or 10 cups of 12.5% chlorinating liquid. This will raise the FC by about 10 ppm.

I wouldn't try to completely battle your algae with your high CYA level. So I suggest you add the chlorine to get the FC level up higher just to prevent the algae from growing as quickly and start draining and refilling your pool by half its water volume so you get your CYA level down to around 40 ppm. You can use a continuous drain/refill method to avoid risk of the sides coming in or you can do multiple drain/refill to a little below the skimmer line (pump needs to be off in that case). This will dilute all your chemicals, not just CYA, but you'll have a much easier-to-maintain pool afterwards. When adding chlorine (bleach or chlorinating liquid) do so VERY slowly over a return and to be extra safe, you can predilute it in a bucket of pool water (say, 2 cups of chlorine in a 2+ gallon bucket, then add that slowly, repeat). This is just being extra cautious -- for Cal-Hypo you would always pre-dilute, but for chlorine pouring very, very slowly is usually OK, but most people become impatient so using pre-dilution kind of forces one to slow things down.

You should immediately order yourself a good test kit. The Taylor K-2006 from Taylor here or from Leslie's here or the even better TF-100 kit from tftestkits here. Your pool store's numbers sound reasonable, but you should really test these things yourself to be sure and its the only way to know how much chlorine you really have since standard kits (OTO and DPD) only test up to 5 ppm while the FAS-DPD chlorine test you will be getting can test very accurately and up to 50 ppm FC so it's good for testing when shocking with chlorine.

By the way, I can assure you that your pool does not have 0 TDS. But that number isn't important.

What was your source of chlorine you were using? Your CYA level got high so I suspect you used Trichlor tabs/pucks or Dichlor powder/granules at some point, is that right? You should instead use a source of chorine that does not have CYA in it -- that is, unstabilized chlorine such as bleach, chlorinating liquid, Cal-Hypo or lithium hypochlorite. Cal-Hypo also increases calcium hardness, but is probably OK for a while since your CH was low, but must be pre-dissolves before adding. Lithium hypochlorite dissolves very quickly but is very expensive. So bleach or chlorinating liquid are your best bet but you must add them very slowly and mix in the pool thoroughly, especially with an above-ground pool since without a floor drain circulation can be quite poor and you don't want the chlorine to settle at the bottom of the pool (it won't if mixed well, but it may if you dump it in too quickly).

Richard

[GoobyGirl]

Thanks Chem Geek for the answers!

I wish I could aerate this pool - I don't even have 10 rowdy boys I could borrow to do this - no kids in the family and only one little child in our neighborhood (small country setting) who isn't tall enough to touch the bottom of this pool. I'm in a pickle, I tell ya. I'm told by the pool store that I don't have any algea at this point - and since there is no floor drain, if things are granules, I premix in pool water anything that won't immediatly dissolve. After anything is added to the pool, I stir that thing up like a giant cauldren ( I can only imagine what the neighbors think!) I have well water so to drain my pool halfway will re-invent the whole metal situation I have since I am on a well and I nearly have all the metals gone! I can't bear the thought of doing this and my DH will probably drown me as I have spent sooooooooooo much time with this pool (I think he's jealous). hehehe.....only to drain partially and start over - I can hear him now.

I was at first using the Dichlor - but stopped about two/three weeks ago - switched to cal-hypo and now I'm using bleach. It was with bleach when I started to get a CL reading of anything!

Don't forget, this is an Intex pool - not the ring type - the ones with the metal pole frame and sucky pump/filtration.

Right now my water is hazy - I can still see the bottom, but its a very faint tinted green (metals) and a bit cloudy - almost a faint mint color. I have a drop test kit, not strips - but I do take my water in to the pool store as they have the more detailed contraption for testing my water. They know me when I walk in. LOL.... I can't get in the water as the nights have been very cool - in the high 50's.... and the days in the high 70's... and we've had about a weeks worth of rain and storms....just my luck (it was a drought prior to my purchasing this pool!). Its suppose to warm up next week. I've enjoyed this pool once - its all new to me but if I can survive this Intex pool - then I can handle a real pool.

I do have a little panty hose sock in the skimmer and I'm changing my filter about three times a day - still rinsing off a LOT of rust from it - then I soak my catridges in some cartridge cleaner for a few hours, rinse them off and let them sun dry. My pump is a 1.5 hp, 1500 gph.

I mini shocked it today and will take my water in Sunday for a reading. They are very understanding and so far have not been very pushy on selling me a bunch of stuff. OH BTW, on July 13th my total dissolved solids were 850, so I don't think they tested them with this last batch as we were concerned at seeing where my metals, CLs, Alk, PH and CYA was....

Next year I'm getting the pool filled by a water truck!

So - I guess my question is this Chem Geek, with the information above, what can I do to assist the haze from lifting and getting this pool balanced out a bit more... or do you want to wait to see what my figures are come Sunday? I also want to mention that I had been adding Iron Out (Summit) and I wonder if this could be causing the haze as well - it has a chlorine nuetralizer and this was the cause of my CL leaving a few times back.... grrrrrrrrr...so, I was adding this stuff only to unbalance my balance. So, no more of that stuff (though it made my water sparkle and clear!!) I just wonder if some of that haze isn't caused by residual 'stuff' from the Iron Out.

Also, do you think I should let the pump rest at some point and just see if anything falls to the bottom? Heaven help me if it does because what I've read on this site is - the vaccum sucks on this pool system also!

I also now have added a 'solar pill'.... can't afford the solar blanket just yet.... I'm almost broke from getting this pool started before I found this site and learned about the BBB method!!

Don't you hate newbies who go out and buy these pretend pools?!?

[chem geek]

Well, your use of Dichlor explains the high CYA level. For every 1 ppm Free Chlorine (FC) you were adding with Dichlor, you were also adding 0.9 ppm Cyanuric Acid (CYA). The Dichlor also explains the low pH because in spite of what pool store folks think, the use of Dichlor is actually acidic (Dichlor addition is only slightly acidic, but the use of chlorine is acidic so the net result is acidic). Since you've got metals in your well water and don't want to do a partial drain/refill, then I suggest you use a PolyQuat 60 algaecide to keep away algae. Before that is done, we've got to get rid of whatever algae is there which may be causing the cloudiness. So don't worry too much about the pH right now since it will rise on its own now that you have stopped using the Dichlor. Go ahead and add the chlorine (unscented bleach or chlorinating liquid) as I suggested to get your chlorine level up higher to around 15 ppm FC and keep it there, which means regular testing and adding more chlorine. This should get your water to clear though it may take a day or two (if it's not too cloudy). You can not only churn the water to mix the chlorine when you add it, but you can also aerate it by pushing the pool brush down into the water from the surface which, when I do this, makes lots of bubbles.

You are going to have a difficult time accurately measuring 15 ppm FC with your drop test. You can try and use the dilution method since your test kit will only measure to 5 ppm, but that's not very accurate. If you can, see about getting the Taylor K-2006 test kit anywhere you can, but most pool stores don't carry it (some carry the K-2005, but that's a 5-drop compare the color test like you already have). The Taylor K-2006 is available a bunch of places online including from Taylor here and from Leslie's here and there is an even better kit based on the Taylor kit but using a more logical size of reagents called the TF-100 from tftestkits.com here. With these kits, the chlorine test is a FAS-DPD test where you add 2 scoops of powder to make the sample turn pink (if there is any chlorine) and then add titrant drops and simply count how many until the sample turns completely clear. You then multiply the number of drops by 0.2 or 0.5 depending on sample size to get Free Chlorine (FC) -- that's it. Very easy and very accurate. No comparing of colors. And it can measure up to 50 ppm FC. You then add another reagent and if there is Combined Chlorine (CC) it turns pink again, then add titrant drops and count them and you get your Combined Chlorine number. Very foolproof. It's the kit that all pool stores should have and also tests pH, Total Alkalinity (TA), Cyanuric Acid (CYA) and Calcium Hardness (CH).

I think the higher chlorine levels will help your situation. Once you've made your water clear and you have no loss of FC overnight and no measurable CC, then you can just maintain 9 ppm FC if you can and add PolyQuat 60 algaecide so that even if the chlorine is lower, you won't get algae (you'll add a maintenance dose of this algaecide every week). This will hold you over until you are able to lower your CYA through dilution or you can just stick with this, but will be more costly due to the algaecide.

See if maintaining the 15 ppm FC and mixing of pool water clears things up -- I wouldn't turn off the pump or use a floc just yet. Your pool didn't sound that cloudy so the chlorine may be able to break everything down on its own and not need physical removal of dead algae. If it appears that the algae isn't dying -- if the green remains, then raise the FC more up to 25 ppm -- with your 80 ppm CYA this isn't actually very high in chlorine even though it sounds like it is -- the CYA attaches to most of the chlorine making it less potent to everything (liner included). To play it safe, measure the CYA with your own test kit before raising the FC above 15 -- the pool store could be wrong, though the high CYA does make sense given the Dichlor usage.

Richard