Starting Over - Need Help

[iowamom]

We have a 350 gallon hot tub with an ozonator that was set-up in mid-September. The water is now a clear green color (not cloudy). I have been relying on those test strips and adding chemicals as needed. Unfortunately, we haven't developed good habits when it comes to adding chemicals. We use dichlor after each use (but we have only been using it 1-2 times a week). A few weeks ago I noticed the water looked green, so I have been adding more dichlor and shocking it with the non-chlorine shock. I bought a Taylor test kit as recommended in this forum, tested the water today and I have found that my CYA is 100ppm. So I am going to drain the pool, start over and I would appreciate some advice.

1. Since my water is green, when I drain the tub do I need to do anything special to clean the interior, e.g., should I be concerned about algae?

2. Can someone advise me on a good chemical schedule? I am realizing that I need to be more exact with my chemical dosing, but where do I start? The guidance given by my dealer is that because the spa has an ozone system, the chlorine level will most likely be low and they advised me not to add more chlorine. So, until now, I have been looking at only pH and TA. Based on 350 gallon tub, and infrequent usage (2 adults, 1-2 times per week for 20 min each), how much dichlor should I add? I would be interested in using the bleach method that has been discussed in previous posts.

3. My calcium hardiness has always been low. I have had some foaming and would occassionaly add Foam Down. Should I add calcium? If so, what is the best way to do that?

Thanks in advance!

Iowamom

[chem geek]

Iowamom,

Clear green is usually something like copper precipitation and not algae (which is usually a more cloudy green), but unless you've used copper via some mineral product or a copper algaecide or had the pH very low and corroded copper from a heat exchanger, then I don't know where it would have come from. It's also unlikely you have algae if your ozonator is working since it should kill free-floating algae. Algae stuck on spa surfaces is another matter, but from your description it sounds like the water itself is a clear green color. I have seen one technical report where monochloramine corroded copper even at the pH that would normally be found in spas so be sure and test your Combined Chlorine (CC) level just in case -- though technically if your ozonator was working it should be oxidizing most CCs to get rid of them. If you can get your spa dealer to test your green spa water for copper, that would be very useful, even if you plan on changing the water (since it can help you prevent future problems).

I don't think the high CYA level is the cause though it certainly can lead to algae growth (if the FC level is not maintained high enough relative to CYA), but usually in pools where there is more exposure to sunlight. If it truly is algae in your spa (which would normally turn dull, then cloudy, before turning green), then you should notice a high chlorine consumption even when not using the spa and would probably measure some Combined Chlorine (CC) as well.

Anyway, to answer your questions, after your drain and refill I would just do an initial shock by adding enough Dichlor to get to 22 ppm FC and 20 ppm CYA which would be 11 teaspoons (3 tablespoons plus 2 teaspoons) of Dichlor in 350 gallons. Then wait for the FC to drop below 10 ppm FC before using the spa and thereafter use unscented bleach (e.g. 6% Clorox Regular or off-brand Ultra) as your source of chlorine adding 3 fluid ounces to add 4 ppm FC after each soak. Measure the FC to see how long it lasts and add more as needed to make sure you have at least some residual at all times and even some (> 0.5 ppm FC) when you next get in to soak. You may need to add bleach in between soaks or may need to add a larger amount after you get out. Be sure to add the bleach slowly over a return flow with the circulation pump running and the jets off (or for extra safety, fill a bucket with spa water, add the chlorine to it, mix, then add the bucket water back into the spa slowly). If you find you are losing chlorine too much when you aren't in the tub, you could try using a higher CYA level since you have an ozonator so could use Dichlor for a longer period of time to cumulatively add another 22 ppm FC and 20 ppm CYA (i.e. another 11 teaspoons cumulatively) and then use bleach after that. Let us know if you do that and if it makes a difference in lowering chlorine usage when not in the spa (we're still figuring this out together).

To minimize foaming, you should raise the Calcium Hardness level to 100-150 ppm by adding Calcium Chloride to the spa. This is very easy to do. You shouldn't need to use any anti-foaming product. You should also make sure your swimsuits are well-rinsed and do not contain soap from their last washing.

Richard

[Hillbilly Hot Tub]

We have a 350 gallon hot tub with an ozonator that was set-up in mid-September. The water is now a clear green color (not cloudy). I have been relying on those test strips and adding chemicals as needed. Unfortunately, we haven't developed good habits when it comes to adding chemicals. We use dichlor after each use (but we have only been using it 1-2 times a week). A few weeks ago I noticed the water looked green, so I have been adding more dichlor and shocking it with the non-chlorine shock. I bought a Taylor test kit as recommended in this forum, tested the water today and I have found that my CYA is 100ppm. So I am going to drain the pool, start over and I would appreciate some advice.

1. Since my water is green, when I drain the tub do I need to do anything special to clean the interior, e.g., should I be concerned about algae?

2. Can someone advise me on a good chemical schedule? I am realizing that I need to be more exact with my chemical dosing, but where do I start? The guidance given by my dealer is that because the spa has an ozone system, the chlorine level will most likely be low and they advised me not to add more chlorine. So, until now, I have been looking at only pH and TA. Based on 350 gallon tub, and infrequent usage (2 adults, 1-2 times per week for 20 min each), how much dichlor should I add? I would be interested in using the bleach method that has been discussed in previous posts.

3. My calcium hardiness has always been low. I have had some foaming and would occassionaly add Foam Down. Should I add calcium? If so, what is the best way to do that?

Thanks in advance!

Iowamom

We have also seen cases in the field that when people spill a beer in the tub it turns a bright green color. Not sure why but it is sure strange!

[iowamom]

Thanks Richard! I drained the pool yesterday and will have my first soak in the fresh water tonight.

Hillbilly--no beers spilled in the hot tub, but I will keep that in mind for St. Patrick's Day!

Iowamom