Another cloudy water thread...can't seem to fix it

[jeremyp]

I've got a cloudy water issue that I can't seem to solve. Here's the background info on everything. The pool was put in last July and filled with fresh water from a pool water delivery truck. The water was clear all last season until the end where we let the pool get a little green prior to closing. The pool builder did the closing for me so I'm not sure what was done to close it up last fall.

Prior to opening the pool two and a half weeks ago, I added a gallon of algecide (not sure of brand) and put the filter on recirculating mode just to get the water moving and circulate the algecide for a few days before fully opening. I kept the safety cover on during this time period. The installer did the opening for me and added a few gallons of liquid chlorine to shock the pool and very quickly the pool water went from green to gray but very cloudy. They also brushed the pool walls and floor and we ran the filter for a few days straight. After a few days, I took a sample to the local pool store (Biolab dealer) and was recommended to add alkalinity increaser, pH down and add shock. (I didn't keep the results from the test).

I have backwashed the filter several times over this period and the backwash water went from being green for the first few backwashes to a a cloudy gray for the past several backwashes. The cloudy condition hasn't improved much at all. Maybe just a bit, but not that noticeable. I started reading on this site and have since got myself a Taylor K2006C testing kit to get ACCURATE testing results. At the time of the pool store testing, I had put in a fresh new canister of chlorine tabs in my autochlorinator and cranked it up to 5 thinking that was a good thing. I just found out today that it's not so I turned it down to minimum. (My CYA had increased from 40-50 to 60 as of today). The chlorine is holding steady and there are no leaves or other gunk in the pool at all.

Here are the results from my testing this morning:
FC 16ppm
CC 1ppm
TC 17ppm
pH 7.4ppm
TA 140-150ppm
CYA 60ppm
CH 130-140

Any ideas on what to do from here? This has been going on for almost 3 wees now and I would have thought it would've cleared up at this point. Any help is very much appreciated.

Thanks,

Jeremy

[aylad]

Hi Jeremy,

Cloudy water can be caused by lots of things...dead algae, calcium too high, "mystery chems" put in the pool during opening, etc etc etc. My first suggestion would be to measure your chlorine tonight after the sun is off the pool, then again in the morning before the sun hits it. If you've lost more than 1 ppm of chlorine in that time, then you're still fighting something in the water and need to get the chlorine back up to shock level, which for a CYA of 60 means chlorine of 20 ppm. (Make sure your pump is off during this time period so that your chlorinator isn't feeding chlorine into the pool and giving you a false reading.) Once you get back up to shock level, you need to test as many times a day as you can, and add more chlorine to maintain that 20 ppm until you're not losing more than the 1 ppm overnight. At that point you can let your chlorine drift back down to the normal range (5-10 ppm).

If you haven't lost more than 1 ppm overnight, then we need to look at your filter. Do you see sand blowing back into the pool? Do you see your filter pressure changing after a backwash? Are you putting the filter through a "rinse" cycle after backwashing before going back to filter mode? Is your pressure rising as the filter runs? If your pressure is rising, then your filter is catching some of the stuff and may just need some time, although I agree that 3 weeks is a little long. The other suggestion I have is to try the DE trick that the other 3 mods use--put a cupful of DE (the media that you use in a DE filter) into the skimmer with the pump running, then watch the returns. If the DE blows out, then you have a filter issue that needs to be addressed. If it doesn't, then the DE will stay in your filter and help the sand catch smaller particles than it would alone. The DE will backwash out with the dirt during the next backwashing, so will need to be replaced after backwashing if you like the result.

[jeremyp]

Aylad, thanks for the reply. I measured 15ppm free chlorine last night at about 9pm and I just checked it again this morning at 7:30am and got 14ppm free chlorine. I don't see sand blowing back into the pool, I do see that pressure drops after I backwash, I do run the filter through a rinse cycle after backwashing until the sight glass is clear and my filter pressure does rise. It rose pretty quickly at first, but now it's rising more slowly. I purchased some EcoKlean cellulose based DE substitute so is that OK in place of the DE? Is it possible that my 1.5 HP pump is pushing too much water through the filter? (just one of my thoughts).

By the way, I'm in NH and the water is still pretty darn cold, if that makes any difference.

Thanks,
JP

[aylad]

It sounds like your filter is working like it's supposed to--maybe the DE trick will help it get the finer stuff. I would hold off on the EcoKlean substitute until Ben or one of the equipment guys says it's okay--some of that stuff gunks up the sand to the point where you'll actually have to replace it, and I'm not sure about that one.

I guess it's possible that the pump is pushing too much water through the filter--I have the same filter you do with a 1 HP pump on it--but again, I'm not an equipment pro, so Ben, Mark, or one of the others will have to take a stab at that one. I would think that if that were the problem, it would also be pushing sand and other debris back into the pool. IN the meantime, just keep the filter running and backwash it as you need to. Remember that a dirty filter works better than a clean one, so I wouldn't backwash it until the pressure is at least 8 psi over "clean".

How does your water look? I know it's cloudy, but is it blue? Green?

[jeremyp]

Thanks. I'll wait to hear the equipment experts...
The water looks great other than being cloudy. It's blue in color but with poor visibility through the water.

[jeremyp]

Here are a couple pics of the pool...