33k Gallon Chemistry Issue?

[tyes]

Okay guys very new to this, first of all this is my reading using a free Aquacheck Test that came in a kit from Leslie Pools:

Free Chlorine PPM: 0.5

pH: 7.8

Alkalinity PPM: 180

Cyanuric Acid PPM : 100

33,000 gal pool open April 17th. Cleaned out the cartlage filter, added more water, and threw 4 gal of chlorine to shock. Water wasnt that dirty slightly green with algae stains. Within the few days it begain to clear up. The pump was on for 3 days non stop. Water became cloudy, added some Ultra Bright Leslie Pool Brand in and in the morning it was crystal clear. I ran the test again, and still my Chlorine was down to "0". I then again clean the filter and added 2 gal of chlorine and ran the pump every 4 hrs per day. It look good for a day and half. Afterwards the pool just seems to get greener and greener per day. I dont know whats wrong, I've test and test and everything seems okay but Chlorine. I cant be adding chlorine this much to keep the pool crystal clear.

My question is what am I doing wrong? I cant be spending all these $ and still no progress. Last year when I bought the house in the summer it was much easier, now opening the pool seems to be tougher. Any advice would really help? I'll take it to Leslie Pool but some times they seem to be selling me a few extra things that I believe I dont need.

[chem geek]

First off, you should get yourself a good test kit, not test strips. Get either the Taylor K-2006 you can get at a good online price here or the TF100 kit from tftestkits.net here with the latter kit having 36% more volume of reagents so is less expensive "per test".

The high Cyanuric Acid (CYA) level in your pool makes the chlorine less effective. You would need to shock with at least 20 ppm or more of chlorine and maintain that level and that would be slow. At 100 ppm CYA, it takes 40 ppm FC to clear the pool quickly so that's impractical. You can do a partial drain/refill to lower the CYA level or you can just try shocking and also add either an algaecide weekly (PolyQuat 60) or use a phosphate remover, both are at extra cost to prevent algae growth. Read more about how to maintain your pool at the Pool School including the article Defeating Algae.

By the way, the Leslie's Ultra Bright is a clarifier so helped consolidate algae so that it gets caught in the filter, but it does not kill algae -- only the chlorine does that.

I'll bet you got into this problem because you used stabilized chlorine products, Trichlor and/or Dichlor, which build up CYA. The following are chemical facts that are independent of concentration of product or size of pool and should be taught by all courses and by manufacturers to pool stores, but is not in spite of it being an indisputable fact.

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.

For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by 7 ppm.

It's hard to believe how an entire industry continues to deceive consumers and dealers by withholding this basic information and how the chemists working for these companies can sleep at night knowing that their paychecks are partly paid for by the deceit which comes from selling more chemicals (algaecide, clarifiers, etc.) to fix the problems caused by other chemicals (stabilized chlorine building up CYA). Some do sell "algae-free guaranteed" packages that include algaecide, but they don't tell you that the reason you need the algaecide is because of the buildup of CYA that makes chlorine less effective allowing algae to grow. Trichlor is convenient since it is slow-dissolving so many people would continue to use it even knowing the truth, but at least they would be well-informed and know how to prevent algae from growing.

Richard

[tyes]

Thank you for the very detail response. YOU are correct, I have been using a stabilized chlorine products,(Chlor Brite Sanitizer ). This has been my only line of defence as to cleaning and maintaining my pool last summer. I actually threw a gal (bag) once a week and used a clarifier every now and then. Obviously this is not going to work this summer.

If adding more of these sanitizer and shocking it more wouldn’t that just bring up the CYA level again. I actually want to eliminate it rite away. As for draining and refill, that sounds to be the best play for me, but I don’t have any special equipment to do so and probaly wont attemp. My pool pipes has a valve indicating “pool drain”. I don’t know if that’s something I can use. If decided to drain how much water would I have to drain out? Worst case, I’ll do what you mention: shock the pool again up to 20 ppm or more to 40 ppm then use a algaecide weekly. BTW I have a couple of question.

When adding chlorin, do I use the same sanitizer or should I try something different?

Do I keep the pump running right after chlorin is in use or shall I let the chlorin do its job for a day or two?

[chem geek]

Chlor-Brite is Dichlor which is absolutely the worst chlorine to use on a regular basis or for shocking because it increases CYA faster than even Trichlor tabs. You should be using 12.5% or 10% chlorinating liquid or 6% unscented bleach. You can find chlorinating liquid at some local pool stores or at big-box hardware stores like Home Depot or Orchard Supply Hardware. If you use bleach, Clorox Regular unscented is the best (it has the least amount of "excess lye" in it) while off-brand Ultra bleaches are also 6% in strength. I prefer to use chlorinating liquid from my local pool store because they reuse the bottles which is even better than recycling them.

You can do partial drain and refill or even continuous drain refill by using a pump such as a pool cover pump. I really think you need to get a good test kit and not use test strips (aka "guess" strips). The CYA of 100 could be more than 100 since 100 is often the limit of the test (depending on how it was measured). Test strips are not very accurate and they can't measure Calcium Hardness (they only measure Total Hardness). You also won't be able to measure high shock chlorine levels unless you dilute the water before doing the test.

When you add chlorine to the pool, you want the pump running and want to keep it running even 24/7 so that the filter can remove the dead algae (I assume the green in your pool is a cloudy green and not a clear green). Please read the Defeating Algae article I linked to. You can use The Pool Calculator to figure out dosing. The key is to maintain a high FC level. You don't just add some chlorine and leave. Initially, the chlorine gets used up fairly quickly so you add it more frequently and as time goes on it will start to hold. You should brush the pool to stir up the algae on the sides and bottom so it can get filtered out and you'll need to clean the filter as the pressure rises. For an example of how a pool can be cleared of algae using chlorine alone, see this link.

Richard