Salt system - bubbly haze from returns

[Jodester]

We just converted to a salt system about a week ago when we replaced our vinyl liner. I am just starting to get a hang of the chemistry balance, but things were going okay. I added CYA and calcium hardness over the past week to get these within normal to high-normal ranges, being sure to do so when the cell is off and keeping it off for about a half hour after adding chemical. At one point, I looked at my SWCG (a CompuPool) and noticed a constant drip from both under the plastic surrounding the cell (ours is vertical) and from one of the connections to the PVC piping, only when the pump is running. Called the installer and left a message over Labor Day weekend regarding this and the fact that for one day, the temperature reading on the CompuPool was oddly reading at 32 degrees F (the water was really around 75 degrees)! Also, salt PPM readings were not staying constant; rather, vascillating between 3200 and 3000 depending on the moment.

So, it appears the pool company came yesterday. I actually forgot to check the leak situation because I was so distracted by a new problem: a cloudy haze pouring in from my pool returns. I do know the company added some more salt (about 3 bags), and the computer is reading now at 3600 ppm. The haze is definitely bubbles, and when I turn off the cell, it disappears within moments. As soon as the cell is turned back on (it's running at 60%), the bubbly haze reappears. It comes out uniformly from all returns, but is most noticeable at the shallow end of the pool where I guess the bubbles congregate more closely. I should also add that since the beginning I have had trouble maintaining a measurable amount of chlorine, but by Sunday I was holding steady at about 1-1.5. However, yesterday when I tested during this whole cloudiness fiasco, my chlorine levels were back down to the reagent test kit barely registering (less than 1).

Some more fun facts:
25,000 gallon inground pool
Sand filter
Attached spa w/overflow into pool
TA: about 165 (according to one expert, high TA is absolutely no concern unless ph is out of range)
PH: about 7.6
CH: about 250 (according to AquaCheck test strip -- need to bring water sample to store for more accurate reading)
CYA: about 60 (according to AquaCheck test strip -- need to bring water sample to store for more accurate reading)
CC: 0
pool is crystal clear other than when this cloudy, bubbly haze appears
Water temp over past few days in the afternoon (we ran heater on Saturday): around 82 deg. F

Any thoughts would be appreciated!

-- Jody

[mas985]

When a SWG is producing chlorine it will also produce Hydrogen gas which shows up as small bubbles out the returns. This is pretty common. However, sometimes it can look like a cloud if the flow rate is low enough such as with low speed of a two speed pump or VS pump.

[waterbear]

Also, salt level fluctuating between two readings is not uncommon when the salt level is between those two readings. SO when your display was fluctuating between 3000 and 3200 your salt was about 3100 ppm.

BTW, high TA is MOST CERTAINLY a concern. It will have a negative impact on your pH stability. Because of the generation of hydrogen that you have observed (and that happens with all SWCGs) there is more outgassing of CO2 and this causes fast pH rise (which leads to other problems, not to mention a huge acid demand).
By lowering the TA ( bicarbonates in the water) you lower the 'carbonation' of the water and therefore, the amount of CO2 in the water. This means less outgassing of CO2 and a slower pH rise (and a lower acid demand) For a SWCg you want a TA around 70 ppm. Since you have a vinyl pool you do not need to raise the CH to compensate for the lower TA since CH is not an issue in vinyl pools unless it is too high (and with a SWCG lower CH is a plus since there is less chance of cell scaling).

Do yourself a favor and invest in a GOOD test kit. Get yourself a Taylor K-2006 (not the K-2005) and do your own water testing! It will save you a LOT of money and headaches in the long run! Since you have a sand filter you will also need to monitor your salt levels and CYA levels since they will drop with backwashing and need to be maintained. You will need a separate test kit for salt. There are drop based kits from Taylor and LaMotte and Strips from AquaChek that are fne for salt. Keep your CYA at the maximum recommended. If meeory serves me correctly CompuPool has a Max of 80 ppm. This will also help with pH stability and acid demand since the cell will have less on time to maintain the desired FC level and therefore less generation of hydrogen and less outgassing of CO2.

[Jodester]

Spoke to my pool guy today -- he just said to superchlorinate to bring up the chlorine level, and that the bubbly haze should work itself out in a couple of days. Does this sound reasonable?

I just want to know -- what caused this? I had been running the pool for 6 days and this only began immediately after a pool technician came, added about 3 bags of salt, and made whatever other adjustments to the equipment. I should add that the cell was on when I came home from work, so I wonder if he neglected to turn off the cell when he added the salt (as the instruction manual says you should do), and that's where this all started.

I tested the water today, and the chlorine is just slightly measurable now (before superchlorinating), at about .5. The TA seems to have dropped ever so slightly to 160. I have to say that it seems to have been dropping in these slight increments for the past several days. When I had a traditional system with an automatic tablet chlorinator, I was constantly needing to bring up my TA. I'd bring it up to 120, then it would drop 10 ppm about every day or two, and when it got down to 80, I'd add Alkalinity Up and start the process all over again. My PH would never move through all of this. So I wonder if something about my water and my filter makes my alkalinity drop on its own without affecting PH. Today my PH was the same as yesterday -- 7.6.

Just curious -- what makes the Taylor test kit so much better than the Leslie's reagent test kit I have now? (other than it also tests CYA and hardness)

Oh, and I should mention that I have a Hayward self-priming pump that does not appear to have any speed settings.

Thanks for your help --
Jody

EDIT by Watermom --- Jody, I combined your two posts into one.

[Jodester]

Okay, here's an update.

I tested the water this morning (it's been running since about 1:00 am with the heat on), after having superchlorinated it beginning Wednesday afternoon (it would have finished some time early in the day yesterday). The chlorine levels are FINALLY at the high end of normal - around 3 ppm. TA has continued to come down slightly to 150.

The bubbly haze is less than it was, but still noticeable on the shallow end. I'm developing a new theory. I may be crazy, but I swear my sand filter sounds different -- noisier. When I look at the sight glass over the valve on the return pipe -- located BEFORE the water enters the SWCG -- there are air bubbles. I wonder if the guy made some adjustment to the sand filter fittings or something and that somehow air is getting into the system somewhere in there. Could this, combined with the natural "carbonation" that occurs in the SWCG itself, be what's causing this haze??

-- Jody

[mas985]

You might have additional air getting sucked in from the suction side of the pump. You can usually tell by the air in the pump basket.

[Jodester]

Okay, more weirdness. A few hours later, I no longer hear the water movement noise coming from my filter, the sight glass by the return valve is clear, and there is no more bubbly haze at all!!

As a side note, why would my readings and that of the Leslie's store for TA consistently be discrepant? They use the same reagents as I do (I use Leslie's), right? This morning my 150 was read by them at 100. This has gone on for years. My reagents were just bought this year, too. ???????

--Jody

P.S. I never saw any bubbles at the pump basket.

[mas985]

Just curious, did you check to see if the SWG was off at the same time the bubbles disappeared?

As for the testing, some pool store employees could really care less about doing an accurate test so it wouldn't really surprise me that they get a different results. Some stores actually use test strips which are not very accurate at all although they have this fancy machine to read the color. TA should be one of the more repeatable test if they are using reagents and if they are then perhaps their reagent is bad, assuming of course yours is fresh.