Pool not Holding FC

[dpoolman]

This is my first post after many hours of reading this wonderful site and following the guidelines posted in pool school. So I've owned 2 houses with a pool the first one was about 25000g sag pool and never had any issues with FC and algae.. My new house is the complete opposite. When we bought the house the person selling it was the pool builder, so it's a huge pool and was unfinished. We had to add a patio, pool fence and permeant equipment. This will be our 3rd season with this pool.. My issue is I can't seem to keep FC in the pool. Last week after getting my new test kit i slammed the pool and it pasted the OCLT test after 2 days. Once the FC levels came down I turned on the SWG to 90% for 12hr a day with a solar cover on. and in about 4 days (1 of swimming) the pool was completely out of FC. At that point the salt level was 3000ppm.

Here are my test levels today since adding liquid chlorine

FC 15
CC 0
CYA 65
PH 7.2
TA 130
Salt 3300
the pool store said I have 16ppm nitrates 2 weeks ago

I'm beginning to think my SWG is not running right or something. I know the salt levels are about 300ppm low for the unit and plan on getting a few bags to raise that up.

Please help I've invested way to much this year already. BTW I live in northern Connecticut.

 

[JohnT]

Welcome to TFP!

Take a sample of the water coming out of a return and test for FC. If your SWCG is working, that water will be higher in FC than the pool water.

Don't worry about the nitrates.

 

[dpoolman]

Ok I'll do that tonight..thanks JohnT

 

[rterickson]

I hate to even say this, but the latest advert from Leslie's says Free In-store Salt Cell Testing.

This may be an option, just don't let them sell you an ozone system, snake oil, or magic beans.

 

[dpoolman]

The only other thing I forgot to mention is that I think my filter might have a hole in it..When I was adding cya to the skimmer some of it was coming out of the return. Also when I've been running the robot the filter is getting pretty filled with what appears to be DE....However the ool is holding FC overnight so I don't see how this could have any effect on the SWG and not being able to keep up....If my salt level is 3300ppm as it reads right now and Pentair says to keep at 3400pp(which seems compared to my old pools autopilot system) shouldn't this be enough to keep up at the levels I have it set up at? Or is it possible when they wired it they didn't hook it up right, meaning maybe 120v rather than 230v? Thanks for the help, the cell is only 3 yrs old and seems to have never worked so just fishing for answers.

 

[karmabiker]

I would second testing water at the jet to see what is coming out. That will tell you if you have a salt cell issue ( most likely)

 

[dpoolman]

Ok So this morning i tested the pool after adding pool chlorine yesterday at I was at FC 15.5 I had the SWG off all day and I just checked the pool FC (it's 8:15pm here) and it's down to 13..This is with the solar cover own and the pump running all day.

I also checked my return with the SWG on 100% just now and FC was 16ppm or 3ppm higher at the return...

Now my SWG manual states that the IC60 will add 2# of pure chlorine every 24hrs of continuous runtime.. I also added another 40# bag of salt so the SWG is now reading 4600ppm which only because the salt hasn't dissolved yet from the deep end.

So with that what should I expect my increase of chlorine should be at, at the return? Any other suggestions?

 

[dpoolman]

any suggestions on my most previous post?

 

[karmabiker]

Is there any scale on the cell?

Pages 22 and 23 of the users manual talk about the cleaning procedure and how to inspect the blades.

Edit - Jason is far more knowledgable on swg than I am. See his post for variance.

 

[jblizzle]

You should only get a slightly higher reading from the return. 3ppm difference is higher than I would expect.

 

[dpoolman]

So to update on this problem. I ended up getting a low reading on my CYA was low about 40 so I added enough to get it to 80...well it brought it over 100 and in doing so my chlorine levels stabilized and I was able to lower my cell run time from 100% down to 20%.

My pool has about 1000 sq ft of surface area along with sunlight exposure about 8-10 solid hours a day. My guess is it the sun was just eating up the chlorine. Next year I plan to shot for about 80 CYA and see where that leaves me...

Thanks for everyones help and quick post.

Time to close up the pool for the season

 

[timerguy]

Next time you add CYA, you'll need to do it in steps so as not to overdose it. Obviously, you didn't get a correct test result before you added it, or possibly your pool isn't 50,000 gals?