Phosphates? High CYA!

Hello there - I haven't posted in a long time because I was really bad being consistent at keeping my ppm's up enough and kept having to deal (often) with algae blooms and do the whole bleach thing. My mom offered to treat having a pool company come and keep the chemicals for me. (They will only do chemicals due to it being an above ground). Anyway, things have been great for many months, but now I have a pond. They were out 2X last week, but it's even worse now. I called the guy today and he said, "Well, then, it must be phosphates." He's coming tomorrow to check.

I went right out to check my chemicals. This is what I found: ppm 1.5 (ugh), ph about 7.6-7.8, TA 100, CYA OVER 100!!!!! (I have the K-2006) Yikes!!!!!

So, I called him back & he doesn't believe that it's that high - he'll check it tomorrow.

I assume from what I've learned in the past, we will have to drain & refill - at least half, right?? Yikes! I asked him what he is using that has gotten the CYA that high. He told me a "conditioner" and that they shoot for a CYA of 80 "this time of year" (I live in Fl & it's getting hot).

Please help me understand this all better so that I may be able to better deal with his suggestions tomorrow. Also, would you say - financially - if this is my responsiblity to fix the problem, or his?

Also - since he is doing a "pool company's" system and not mine, how does that work - they only come 1X a week, so there is no way he could do it my way - I was having to check and balance every day or so when I wasn't dealing with a bloom. How in the world do pool companies only come 1X a week and be successful (usually)? My mom has had hers done for 8 years now and has never had a problem. Never green once.

Thanks for any info.

BTW - I have a 24' round and DID end up buying the correct sized pool pump that you guys had recommended to go with my filter.

Jennifer

The problem's not phosphates, it's your CYA level of 100+ and only 1.5ppm fc.

You do have a couple options.

The first thing you need to do is figure out where your CYA really is. You can do this by diluting your pool water 50/50 with distilled water from the grocery store and testing CYA. Then multiply your result by two.

Your options will be.

1. Keep chlorine levels high based on your CYA content and Ben's best guess chart here: http://www.poolsolutions.com/gd/best...ine-chart.html
2. Do a partial drain and refill to reduce your CYA level in the pool.

With a CYA in the 100-200 range you need to have your free chlorine level between 8 and 15ppm. 1.5 is not nearly high enough. That's for normal operation to keep it clear once it is clear. Since you're green and swampy you need to shock. That means get your chlorine level above 25ppm and keep it there until your water is totally clear, then you can let it drop down to the 8-15 range. While you're shocking, run your pump 24x7 and clean the filter whenever the pressure gets 10psi above where it is right after you clean. That might be daily or even more often with a bloom.

When you add chlorine you need to be using Sodium Hypochlorite (aka Liquid Chlorine or Plain unscented household bleach). Do NOT use dichlor or trichlor as both will increase your already high CYA.


As far as how they do it successfully? You're looking at it. When you spend money with them, they are successful! Right now, I bet you're considering paying them to take care of phosphates... but if you maintain a proper level of sanitizer based on your CYA level, phosphates are a non-issue. It's true they are "algae food" but if you kill the algae with bleach then it doesn't matter.

"Phosphate removal" became very popular with pool stores and services for a while until international relations cause the supply of a key ingredient, a lanthanum compound, I believe, to become unavailable. But it was always nonsense for 99.9% of the people sold it, if not 99.99%! Many people here have phosphate levels that would have pool stores winning Oscars with their dramatic eye-rolling, yet have perfectly clear, safe pools.

It's all about the chlorine!

I hate to say it, but you've obviously not been following the suggested courses of pool maintenance we recommend. Kelemvor has given you good advice that will save you money and I'll add this:
1) test your pool water AT LEAST 2x a day, 3x a day if you can manage and ALWAYS raise your FC back to 25ppm if it's below that.
2) Vacuum your pool to waste every single day until it's clear.
3) Brush your pool every single day to knock algae loose from the walls and floor. Not sure why, but when loose it's more vulnerable to the chlorine.
4) P.O.P.P. needs to be maintained 24/7. That's Pool Owner Patience and Persistence!

Assuming the pool service was not using Trichlor pucks, they could visit once a week and add chlorine by having the CYA be high so the chlorine lasts longer and start the week with around 14 ppm or so and may end up at 4 ppm or so a week later. However, in your case, it sounds like it got out of hand and the chlorine wasn't lasting well enough so algae was able to grow when the FC got too low.

After the pool company owner came out and saw that the CYA really WAS that high, he agreed to a partial drain & refill. After talking to him, it seems an employee probably shot the CYA really high & skipped a few visits. He had similar issues with other clients and employee has been fired. With all of that said, my pool is still green ( I was away for 2 weeks), the CYA is still too high (90ish) and the chlorine is at 1ppm. Ugh. So he is obviously not dealing with the problem properly and I will take my pool care back into my own hands. I STINK at being consistent, so this is hard for me, but I will do my best.

I have forgotten how much bleach raises 1 ppm for my pool - could you please refresh my memory? I think it was 1/2 bottle = 1 ppm, but I'm not completely sure. I'm a 24' round - above ground - 13,000 gallons (I think).

Here we go again.

Thank you,

Jennifer

In 13k gallons of water, 1 gallon of 6% bleach will give you 4.75ppm. So if your bottle = 1 gallon, 1/2 of that bottle gives you about 2.4ppm. At 90cya you need to be over 20ppm to shock.

This is based on the best guess chart and your 90ppm cya. You need to KEEP it above 20ppm and keep testing for combined chlorine until your CC is 0, and you don't lose more than 1ppm FC between sundown one night and sunup the next morning.

Once that happens you can let it drift down to 5-10ppm for regular operations. I keep my pool at that level of CYA (because my swcg recommends that level) so you can definitely run your pool at 90ppm cya.

If you're not diligent enough to maintain things on a regular basis - and don't have a metal pool - then you might want to consider a salt water chlorine generator. You still have to stay on top of your pH (I usually dose with acid about once a week). A swcg won't help you clean up the mess though; you're going to have to do that the regular way.

Thank you so much!

Question - would adding extra bleach buy me more time between checking/adding or make this process go more quickly or would it just waste bleach? Ex. if I'm supposed to keep the level above 20, would it speed things up to keep it above 30, etc.?

Thanks,

Jennifer

For shocking, a higher FC level makes things go somewhat faster but the chlorine losses from sunlight are greater since they are based on the percentage of FC. However, speeding up the algae kill isn't the slowest part of the process. The slowest part is then removing the dead algae via filtration.

As for regular maintenance, starting with a higher FC level will have it last longer, but because it drops as a percentage of FC you will be using more bleach. It's not "wasteful" so much as a trade-off between convenience of not adding chlorine as often vs. the extra cost associated with the larger amount of bleach that is needed.