Pool Chemistry CYA and CH high, need advice.

[Absoloot]

Italics is background info, if TLDR.
My family inherited a piece of property from my grandfather and started managing it last year. Property has an old (60s) plaster pool, ~25k gallons, that we need to take care of.

Long and short of it is, my dad hired a guy to maintain the pool from a local small business (SoCal), and 6 months later in December our pool turns deep, deep green. Nasty stuff. Pool guy says its not his fault, we need a new pump. Obviously that's BS, and we fired him. So begins my time managing the pool.

Went to a local pool story run by an older guy, not corporate. He gave me some good advice, and I slammed the pool with liquid chlorine, kept adding day after day and brushing until it was clear. Then we vacuumed up the particulate, pulled the filter, and deep cleaned it with bleach taking it apart panel by panel. Problem solved, pool was crystal clear and algae free. Now, at this point I should mention the pool guy wasn't completely lying, the pump that was managing the pool was an old 1 HP above ground pump, the kind that comes in a pool kit for putting together an above ground pool for the summer. It was absolutely old and not working great, so we sprung for a decent pump, the SuperFlo.

Now, at this point, its winter and no one is swimming and the pool was fine for months, but recently (May-Current), I've been having issues with algae cropping back up. Several times I took water to Leslie's and they say you're chemicals are fine etc etc. So I keep spiking the chlorine whenever I see a bit of green creeping in, and pulling the filter and cleaning again a few days later. This cycle has happened 3 times so far this summer and its getting infuriating.

So I do some research, find troublefreepool, read the documentation, and pull the trigger on a TF-100 Test kit.

I just spiked the chlorine with a store bought shock a few days ago, then tested the waters. Here's the data:

FC: 25 ppm
CC: 1.5 ppm

CYA: ~160 ppm
CH: 825 ppm
Tap CH: 300 ppm (this is what the pool gets filled with, municipal water supply)
TA: 120-130 ppm

So CYA and CH are very high, and need to come down. So I need some advice. Everywhere I look people are saying that draining your pool is the fix for both, but I don't even know where to begin to drain a pool this size in the ground. I've also read that letting pool plaster sit in dry hot weather is bad for it, so all told I'm quite worried about how to proceed. Any advice you guys could give would be greatly appreciated. Thank you for your time.

Regards,

David

P.S. Attached are pictures of my pump, fitler, and piping. There are four outlets into the pool from the pump, I've attached a picture of one, and I've moved the bottom cover to expose the outlet at the bottom.

 

[Texas Splash]

David, good work with the TF-100. Before you waste too much more chemicals, your TF-100 instructions confirm that your CYA is way too high. Probably from pool store tabs and powdered shock. The only way to lower CYA is water exchange. In your area, a CYA of about 40-50 is ideal, and since you need to follow the SLAM Process to remove algae, a CYA of 30 would be a perfect world number. But I know that's a lot of water exchange, but you need the CYA at least down to 70 or below. Easy math, changing half the water lowers your CYA by 50%, so keep that in mind. That might also help to lower your CH as well.

Once you exchange enough water to get the CYA down to 70 or below, you can then begin the SLAM Process to kill the algae once and for all. When you do the SLAM, make sure to remove the pool light and set it on the deck (power off), inspect under the main drain cover, etc. Anywhere that algae can hide. Give that some time to process and let us know if you have more questions.

 

[Msch99]

You can exchange water also. Takes longer and not as efficient, but doesn't expose plaster/chance of floating pools.

Draining/Further reading

 

[Absoloot]

So I have a DE filter, but I don't know what MPV means? I attached pictures of my plumbing, is that have to do with the valvle/piping set up? I'm trying to figure out how to safely drain my pool and I figured I'd do it in increments rather than try to drain half and fill half.

I have a nearby Home Depot that does rent Sump pumps, but that seems like a pretty extreme action and could flood my yard. Any advice as to how to actually, safely and successfully drain my pool would be appreciated.

 

[mknauss]

You do not have a MPV valve.

Typically you would drain to your sewer clean out. Or your municipality may have some standards on where you are to drain to.

 

[Texas Splash]

MPV stands for Multiport Valve. You don't have one, you have a plunger/slide backwash valve, so you can't backwash to WASTE. You'll need a separate sump pump.

 

[Absoloot]

Could I use the filter drain to exchange water? For some reason my drain has a valve rather than a plug, so I can gate the drain rate. I was considering if I could try to match it to the intake rate of the pump so the filter stays relatively full and slowly exchange water that way. Otherwise, I'll have to rent a sump pump.

 

[Texas Splash]

Could I use the filter drain to exchange water?

You can. I have one as well. They are a bit slow, but that's okay. If you have any extra garden hoses, you can also get them started by siphoning for extra relief.

 

[Rancho Cost-a-Lotta]

I have a nearby Home Depot that does rent Sump pumps, but that seems like a pretty extreme action and could flood my yard. Any advice as to how to actually, safely and successfully drain my pool would be appreciated.

Check with your water utility and/or City for guidelines/requirements for draining pools. Some allow discharge into the storm drain (street/gutter) and some allow discharge into the sewer. Some areas require a discharge permit. Google "City of XXXX, swimming pool discharge guidelines."

Best of luck!