High CYA Level

[Jpostle]

So I have an extremely high CYA level for my pool. Pool builder does not recommend draining the pool, recommends leaving as is and adjust the FC level. The pool is just over 1 year old and at this point I am not sure how the CYA level got this high. No issues with algae until a few weeks ago. I picked up the Taylor kit 2 weeks ago to help trouble shoot the problem. Readings as of tonight are as follows:

FC 12.2
CC 1
PH 7.4
TA 110
CH 210
CYA 100+

So my question is, what level should my FC level be? Algae build up is a problem with the pool right now, but that’s expected given the CYA level. Is it trial and error on the FC or should I be shooting for a particular level?

Thanks for the help

 

[mknauss]

Welcome to the forum! :handshake:

You can do a dilute test for CYA above 100. Step 8 in Pool School - CYA

Use [FC/CYA][/FC/CYA] for the appropriate FC.

Your CYA in a non - SWCG pool should be in the 30-50 ppm range.

You can exchange water instead of drain and refill. Let me know if you would like the details to achieve that.

I suggest you read Pool School - ABCs of Pool Water Chemistry and consider reviewing the entire Trouble Free Pool School book.

 

[YippeeSkippy]

I wonder- are you using chlorine pucks to sanitize your pool? If so, did you know that for each 8ppm of chlorine a puck gives you, it *also* gives you 6ppm of CYA!

Pool stores fail to mention that little problem when selling you those darn things, huh?

Our TFPC method suggests only using liquid chlorine (aka bleach) or a salt water chlorine generator. Save the pucks for times you actually *need* to increase your CYA or when going on vacation as long as your CYA can tolerate the rise.

Maddie

addendum- your CH is a touch low also. Please refer to this --> Pool School - Recommended Levels
Low calcium in the water will leech calcium from your plaster walls. No bueno!

 

[ctrav]

Welcome to TFP...

Lots of folks have had this issue and it can/will be fixed if you adhere to TFPC methods and follow the advice.

 

[Jpostle]

Thanks for the response. Unfortunately I came late to this forum, it I’ve learned a lot already. Understood on the on the appropriate CYA level and I hope to get it back to where it needs to be! That would be great if you can share the details for exchanging the water. I guess my dilemma right now is that based on the FC/CYA chart, my FC is where it should be when CYA is 100-200 and I continue to have algae problems.

 

[mknauss]

Do the dilute test for CYA described above. A range of CYA you state would have a huge range of appropriate FC.

You can exchange some water without draining.

If you place a low volume sub pump in the deep end and pull water from there while adding water in the shallow end (through a skimmer or into a bucket on a step so you lessen the water disturbance) you can do a fairly efficient exchange. That is assuming the water you are filling with is the same temperature or warmer than your pool water. If your fill water is much cooler than your pool water, then switch it. Add the water to the deep end (hose on bottom) and pull water from the top step.

The location of the pump and fill hose may change if you have salt water, high calcium, etc.
In my pool, with saltwater and high calcium when I drain, I put the pump in the deep end and hose in shallow end. The water in the pool weighs more per unit volume than the fill water from the hose.

Be sure to balance the water out and water in so the pool level stays the same. Also be sure your pool pump is disabled during this process. Once started do not stop until you have exchanged the amount of water you wish.

 

[Jpostle]

I had read some other posts about cya in the chlorine pucks. Looking at the pucks I’m using that doesn’t seem to be the case based on the ingredients listed, trichloro s triazinetrione 99%.

 

[mknauss]

Triclor adds Chlorine and CYA to your water. For every 10 ppm FC you get 6 ppm CYA ---

All forms of solid chlorine add something else. Trichlor and dichlor it is CYA, Cal Hypo it is calcium.

 

[Jpostle]

Well that reinforces the need to ditch the pucks and stick with liquid chlorine! Using the diluted cya test, the level is 180ppm.

 

[mknauss]

OK -- so you need to do a 75% exchange. That will get you to around 50 ppm CYA.

Pucks have their place. Just not for daily maintenance. Keep them to use when you are gone for a few days or a week and no one can add liquid chlorine.

Eventually you will want to consider a SWCG. Let it make your chlorine.