Calcium levels in Plaster SWCG pool

[tomfrh]

I have a SWCG pool with plaster finish.

My SWCG spits out calcium chips which the robot (or me) eventually vacuum up and discard.

My CH levels are down to 200. This site says it should be 350-450

should I simply add calcium to keep the levels up?

Any other advice?

 

[cfherrman]

What's your fill water ch? If it's low add some calicum, if high it's usually best to let the fill water take care of that.

Post up a full set of test results, something is not balenced

 

[tomfrh]

Im in Sydney. Fill water ch is ~50


other results
FC 13 (been slamming)
ph 7.2
cya 70
TA 200
salt 4000
ch 200

 

[CaptainUnderpants]

Hmmmmmm....... My SWG used to spit out calcium chips as well. My assumption was that my calcium level was too high, but my conclusion was that my ph was too high allowing scaling. Once I the pool got past the one year mark and I lost my fear of using MA to keep PH under control I haven't had the calcium chips coming off the SWG. But now your post is making me question the cause and effect relationship of high PH and calcium chips.

My pool did start to get some scaling when I had high PH, but this has since been eliminated by maintaining a proper CSI. With your numbers, pool math shows a very low csi of -.4, so I am at a loss. Maybe it is a function of new plaster, as I had the calcium chips when my plaster was new...?

 

[tomfrh]

The calcium chips are the SWG reversing polarity to prevent scaling build up of the cell.

saves you having to clean the cell.


mine used to spit out a lot more calcium when calcium was previous far too high , due to too much economy calcium based chlorine. The SWG seems to have cleared a lot of the calcium that way.

The 50ppm fill water will also have been reducing the CH

 

[Dirk]

Yes, but was the CSI high before the slam? Reason I ask... When I first started up my SWG, it was under the management of a pool guy. My water balance was surely off, and my SWG started throwing flakes. I fired him, took over the pool and closed down the SWG for the winter. A few weeks ago, my SWG started throwing flakes again, but this was after months of perfect balance, and without the SWG ever having been turned on!

I cleaned my SWG the other day (still before ever turning it back on), and there was plenty of calcium deposit on the plates.

My theory (and it's only that) is that the SWG plates got the build up when first used, when the water was first out of balance, and retained the build up for months. Something later freed the calcium from the plates (perhaps good TFP water?) and the flakes reoccured.

Point being, I got the flakes even well after my water was perfect, and well after I had shut down the SWG, so in my case, I think my present water condition and balance had nothing to do with creating the flakes, maybe just cleaning them off the plates and throwing them into the pool.

I think I read here that it is possible to reduce calcium build up with water chemistry. So maybe that's in essence what I inadvertently did.

So maybe just get the water TFP perfect, clean your SWG, and that'll be the end of it... (That's what I'm doing now.)

 

[CaptainUnderpants]

The calcium chips are the SWG reversing polarity to prevent scaling build up of the cell.

saves you having to clean the cell.


mine used to spit out a lot more calcium when calcium was previous far too high , due to too much economy calcium based chlorine. The SWG seems to have cleared a lot of the calcium that way.

The 50ppm fill water will also have been reducing the CH

I should have added that my CH is 400 and I am getting no calcium chips. I believe the calculated CSI is the overall determining factor with regards to CA buildup, and the biggest contributing factor to a high csi is ph. But your csi is very low right now. Did you just drop your PH?

 

[cfherrman]

Ta of 200 your oh will be in the 8's or close to it every day, check pool math and see what the csi is with 7.8 or 8.2 pH. After that check out the csi with ta 100 and ch 300 with pH 7.4-7.8

 

[CaptainUnderpants]

Ta of 200 your oh will be in the 8's or close to it every day, check pool math and see what the csi is with 7.8 or 8.2 pH. After that check out the csi with ta 100 and ch 300 with pH 7.4-7.8

Good point with a TA of 200 PH should be much higher than 7.2 and always floating up.

 

[tomfrh]

I should have added that my CH is 400 and I am getting no calcium chips. I believe the calculated CSI is the overall determining factor with regards to CA buildup, and the biggest contributing factor to a high csi is ph. But your csi is very low right now. Did you just drop your PH?

I added acid a few weeks ago.

The pool chemistry is in a state of flux at the moment. I've been slamming and am starting to dial everything in. So yes maybe CSI was causing the calcium chips.

- - - Updated - - -

So maybe just get the water TFP perfect, clean your SWG, and that'll be the end of it... (That's what I'm doing now.)

Yep, that's what I'll do. Thanks.

 

[cfherrman]

After slam fix your ta by doing the acid and areation method to prevent flakes

 

[tomfrh]

After slam fix your ta by doing the acid and areation method to prevent flakes

Yep, will do. Thanks.

How much does aeration speed it up?

 

[Dirk]

Quite a bit, but It’s logarithmic. It goes pretty fast at first, about TA10 a day with the amount of aeration I was using (three sprayers attached to returns), then tapers over time. Towards the end it’s a bit of a losing battle, so you just stop and let the TA find its natural level.

 

[tomfrh]

Quite a bit, but It’s logarithmic. Goes pretty fast at first, about 10 a day with the amount of aeration I was using (three sprayers attached to returns), then tapers over time. Towards the end it’s a bit of a losing battle, so you just stop and let the TA find its natural level.

If you didn't aerate at all how much change? Half as fast?

 

[Dirk]

If you didn't aerate at all how much change? Half as fast?

Sorry, not sure. I didn't do it that way. Someone else here would know... I guess it would be somewhat dependent on your fill water, too. I got it down from 160 to about 90, then sorta forgot about it. It now seems to hover around 75...

 

[cfherrman]

Yep, will do. Thanks.

How much does aeration speed it up?

You have another thread here almost dealing with the same questions right? Fill water ta 75 and ch 75? If so just top up the ch to minimum and just hit your pH down as needed, I thought you were going to be fighting high ta fill water. If I'm thinking of somebody else disregard.

 

[tomfrh]

Yes the pH/TA questions should go in other thread. sorry, got off track..


Ive now added 6kg of calcium chloride. I’ll retest tonight. Hopefully this will have raised CH to around 300. I’ll do the final raise tonight based on the reading. Should I aim for 350? Or take it to the higher end (450) given my fill water is soft (ch 50) and no other sources of calcium I’m aware of.

 

[Dirk]

Yes the pH/TA questions should go in other thread. sorry, got off track..


Ive now added 6kg of calcium chloride. I’ll retest tonight. Hopefully this will have raised CH to around 300. I’ll do the final raise tonight based on the reading. Should I aim for 350? Or take it to the higher end (450) given my fill water is soft (ch 50) and no other sources of calcium I’m aware of.

Not sure what the best strategy is for CH, but just pointing out: Unless you replace high-CH pool water with lower-CH fill water (due to splash out or backwashing or whatever), even CH50 will eventually increase CH, as it doesn't leave the pool with just evaporation.

What I haven't yet figured out for my pool, as I have CH-zero fill water, is should I dial my CH to 350, 400 or 450. I'll likely first see where my pH settles, then use CH as one of the "tools" to keep my CSI where I want it...

 

[tomfrh]

Oh right, the fill water CH accumulates with evaporation...oops

I suspect i drain more calcium than I add via the hose, but for now I will get it to 350 and then monitor.

 

[cfherrman]

It depends on your amount of rain, splash out, and evaporation.

More rain and splash out = 350 and watch your minium

Less rain and more evaporation, 300 and have a slow rise