My water needs help

[PoolDoc]

The fact that the water was clear, but became cloudy after vacuuming, is pretty strong evidence of under-performing filtration.

This problem is very, very, VERY common on above-ground pools, since AG pool kits almost always match an undersized filter with an oversized pump. This causes a variety of problems, but with sand filters, it usually results in the loss of sand with each backwash.

Unfortunately, since sand filters sold with AG pools are almost always top mount valve, rather than side mound valve, adding more sand is a PITA.

[Bosch232]

I vacuumed all that algae to waste, so it shouldn't have gone through the silica sand. But...

I'll look into the filter. I think I replaced it (and the sand) 3 yrs ago. Maybe 4.

I'll report back.

[Bosch232]

Monday afternoon, home from work and a curious development..

The milky cloudiness has dissipated, and viz improved from 16" to 23".
The chlorine level REALLY dropped off since last night, from 12.5 down to 5.5 now, 22 hrs later.
The color has changed to a typical green algae color. But the clarity is improving.

So for the moment I backwashed (it came out pretty dirty) and I'm going to bring it back up to superchlorination level (about 15) by adding just under 2 gallons of bleach. I'm discontinuing the dichlor for now bc it seems to be driving the CYA up higher than I'd like. (100 ppm).

Also aerating for a bit to bring the pH up a little. It's steady at 7.0.

More to follow.

[PoolDoc]

1. If you vacuumed to waste, then the cloudiness was probably algae stirred up by the process, rather than algae blown through the filter

2. If your CYA > 70 ppm, you DEFINITELY need to stop the dichlor. In my area, at least, Walmart has restocked pool grade (10%) bleach. You could use cal hypo, but if your calcium + alkalinity levels are high, doing so might cloud your water.

3. The fact that your backwash water was dirty from algae is a fair indication that you DO have enough sand.

4. Aerating only raises pH IF the alkalinity is substantial.

Good luck.

[Bosch232]

Well tonight I did a very smart thing: I took Pool Doc's advice.

I took apart my filter and checked the sand.
See where I'm pointing? That's all the sand left in the filter.
This explains a lot of last year's frustrations as well.
Honestly, it never occurred to me that I could be losing sand out of the backwash.

I do agree that the dichlor has gotten the CYA out of hand.
First things first: Purchasing silica sand from Concrete Industries tomorrow.

[PoolDoc]

Wow! Even I'm surprised that it is THAT low.

Thanks for posting that.

Keep in mind that you'll need to reduce the backwash flow, or it will happen again. The fastest short term solution is a valve on the discharge line, allowing you to throttle flow.

Long term, a smaller pump OR a smaller impeller in the existing pump -- assuming you can find the parts -- will not only save your sand, but will improve filtration. Excess flow not only causes sand loss during backwash, it also causes dirt to be driven THROUGH the sand bed, and back into the pool!

Good luck!