High Phosphate Levels Causing SWG to Underperformed??

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sendsley

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Jun 26, 2014
41
Shawnee, KS
My Breeze SWG doesn't seem to be keeping up, and running at boost level of overnight only increases FC by 0.5 despite being a 20k gallon capable SWG the on a 11k pool. I've recently completed a SLAM and have passed OCLT the multiple times.
Talking to the pool installer about replacing it as its under warranty but they are claiming a high phosphate level is why it's not keeping up and saying FC level should equal TC otherwise the phosphate level is too high.
Using Taylor test kit I do seem to have a high phosphate level despite sparkling clear water and consistent passing of OCLT thanks to TFP
So my question is, can a high phosphate level impede the SWG the from producing enough chlorine?
And what is the best way to lower phosphate level?
 
Forget about phosphates. They won't do anything. The installer's claim about FC and TC being related to phosphates is nonsense.

If you're maintaining the correct FC for your CYA, then you won't have any problems.

Can you post a full set of test results?

If your cell is not scaled and there are no error codes, then the system is probably working properly. Most likely, the FC is not being kept high enough for the CYA.
 
That's just it, struggling to keep FC levels up even with SWG on BOOST all the time.

Tuesday 7/22 955am
FC 2.11
TC 2.19

Tuesday 7/22 845pm
FC 1.26
TC 1.49
PH 7.6
TA 155

Salt 4200 (right in the middle of the 4000-4500 recommendation of the manual)
CYA 66 as of 7/11
 
Only 3 options really

1. The CYA is too low and the sun is consuming FC faster than the SWG makes it.

2. The SWG is dirty and not producing.

3. Something is in the water consuming the FC and you need to follow the SLAM process ... without the SWG ... with the FAS-DPD test.
 
If you aren't losing chlorine at night, it seems like the two remaining options are that the generator isn't producing enough chlorine or you are losing it from sunlight.

Collect a sample of water from a return as PAGirl suggested.That will give you an idea of the generator's production.

How confident are you of your CYA test result? Low CYA would give the same symptoms. Check out the extended CYA test instructions to verify your process http://www.troublefreepool.com/thre...Kit-Directions?p=203524&viewfull=1#post203524
 
My question is how do you know you are passing the OCLT? Those test numbers do not look like they came from one of the recommended test kits we suggest. What test kit are you using? We will solve this for you but we need to eliminate some of the basics first.
 
Run another OCLT tonight and make sure the SWG is off. Raise the FC to around 7 or more for the test, I like to raise mine to 10.

The chlorine level is low for the CYA level, so there might be a chance some algae is starting to grow again.
 

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If you targeted 8ppm now ... it is going to be significantly less by tonight. You should test this evening and maybe add more chlorine if the FC is lower (and then test again after 30-60 minutes).

SWGs only add slightly more FC to the return water.
 
Phosphates are BS. They can not and will not inhibit chlorine production.

I had a similar issue about a month ago - my water was very slightly cloudy and the SWG was running at 90% and couldn't keep up. Turns out my CYA was too high (~150ppm) and I had an algae exposure from my waterfall (one of the small basins in it had gone green). After getting my CYA right and SLAM'ing the pool, my FC levels are now stable and the SWG runs at 40% with an 7 hour daily pump time.

I'm going to agree with others who posted that your CYA level could be too low (CYA 60-80 ppm for an SWG pool) and/or you are on the verge of an algae bloom. You should NOT be running your SWG on BOOST mode all the time as that will only degrade it's useful operating lifetime.

How are you measuring CYA? Strips are not accurate. ColorQ has known limitations that are well documented on the TFP forums. Only the melamine-based black dot occlusion test really works and that takes a lot of practice. To do it right, you should purchase the 50ppm CYA standard solution so you can train your eye to see how the dot should disappear.
 
Just did a few additional tests, CYA with Taylor is showing more like 100 for CYA (am I supposed to hold down at belt level?) while LaMotte shows only 60 still. So low CYA doesn't seem to be the problem, high CYA a more likely problem I guess????

FYI, FC with Taylor 6, CC 0
with LaMotte from same sample FC 5.46, CC 0.08

Will run OCLT again tonight after adding more bleach to get level up.

But I think what I'm hearing is that high phosphates are not the problem, it's more likely the SWG just isn't doing a good enough job. It is producing chlorine - I can see it in the tube.
 
The LaMotte ColorQ is inaccurate for CYA at or near max values. It has many known problems and most forum users don't trust ColorQ's accuracy. You can search the forums and see plenty of threads about the ColorQ issues.

Taylor test is much more accurate. To calibrate your eyeball for the Taylor test, you should purchase the 50ppm CYA standard and then perform the turbidity test in it. Then adjust lighting and eye to sample tube distance until you no longer see the black dot. Those lighting and distance conditions are then the ones you should use on your actual pool water tests.

Your next step should be to take a sample of pool water and dilute it by half with tap water. Then re measure CYA on the Taylor test and multiply result by 2.

I think your problem is your CYA is way too high and it's effectively locking up all of your FC so that it is ineffective.

Your SWG is likely fine. It just can't produce enough FC to overcome your high CYA. That was exactly the problem I had, my CYA was 150 and my SWG simply could not produce enough chlorine to overcome the buffering effects of CYA.


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I retested CYA with the Taylor kit and a diluted sample, CYA levels more like 110-120.

OCLT was again passed, with SWG off of course 5.30 at 11pm last night, 4.62 this morning, CC still well below 0.50. I know those aren't from the Taylor test kit but for FC and CC I've done dozens of tests on the same sample and Taylor vs LaMotte are always the same and I didn't have time this morning for anything else.

But, the OCLT would indicate algae is not the problem.

So I'm back to the question of why isn't my SWG keeping levels up? Is it just not capable of keeping FC at high numbers required with CYA so high?
 
sendsley said:
So I'm back to the question of why isn't my SWG keeping levels up? Is it just not capable of keeping FC at high numbers required with CYA so high?
Click to expand...

So to summarize (correct me if I'm wrong):

Salt is good
CYA is high or at least high enough
Water looks good
SWCG is big enough for the pool and is producing at least some chlorine
Pump is running 24/7
You aren't losing much chlorine overnight

and last but not least

Your SWCG isn't keeping up.

High CYA only becomes a real problem when you get algae. Without that, your chlorine will tend to hang around for a long time. Just the opposite of what you are seeing.

How about bather load? How many swimmers a day and ages?

Have you cleaned the cell of your SWCG?

You might try taking a water sample from the return using a pool noodle or your vacuum hose to route the return water to the surface directly into the bottle to make sure it's a pure sample of the output of the generator and test that.
 
I have been cleaning the SWG cell, it's not perfectly brand new sparkling clean but it's not dirty either.

As for bather load, at most 4 of us recently, did have about 10 kids in it a week ago but the last few days 2 for a few hours on Tues and Weds, nobody yesterday - so light load.

I have taken samples directly from the return and they are typically only slightly higher (less than 0.5) than the previous "regular" reading.

The water is sparkling clear and I'm happy with it except that I keep having to manually dose even with the SWG running.
 
CYA of 110-120 is waaaay too high!

Your CYA for an SWG pool should be half that (60-80).

When I was running my SWG at 90% all the time with a CYA of 150, I could barely get the FC value above 2. That was totally inadequate.

If you read the CYA/FC relationship sticky, you'll see that, in order to have disinfecting levels of chlorine in a pool with CYA over 100, you'd need A LOT of FC. Every SWG is limited in how much chlorine it can produce in a 24-hour period. My Pentair IC40 can only produce 1.4lbs of chlorine per day, that's it, no more. When my CYA was too high, essentially all the chlorine got bottled up and was unable to disinfect.

You need to do a partial drain and refill to get your CYA down. For SWG pools, the proper water chemistry levels can be found in this link .

As for the ColorQ vs Taylor, yes you will often find them to be close on some values (FC & CC) but way off or inconsistent on others (CYA and CH). ColorQ's often work great at first and then, over time, become unreliable. Like any electronic measuring device, it needs calibration to keep it working correctly. Given this wide range of variability with ColorQ's on these forums, most TFP senior members and experts don't trust results from them and prefer measurements based on Taylor drops (either K-2006 or TF100).


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We are having major phosphate issues in Florida as well. The SCG's are unable to Keep up with all the rain dilution, sun, bather load, and the airborne Phosphates and Algae. One being a plant and the other a fertilizer. Once the phosphates are removed, the algae no longer has a food Source and is easier to kill and the chorine can then be maintained.
 
There seems to be a perception that phosphates have more of an impact than they actually do. There are several TFP members that have phosphate levels well into the thousands (ppb) and have never had a problem with algae. The key is to maintain adequate chlorine to CYA ratio. If a SWG is not keeping up in maintaining the proper chlorine level, these are the likely culprits:

  1. The CYA is either too low (resulting in a high loss of chlorine to sunlight) or too high (SWG cannot produce enough chlorine to maintain a level that is sufficient for the CYA)
  2. There is something growing in the pool such as algae that hasn't bloomed. Clear water does not necessarily mean that it is properly sanitized.
  3. The salt cell may need to be replaced
  4. The salt level of the water is too low
  5. There is an unusually high bather load. This may necessitate supplemental dosing with bleach in order to maintain proper sanitation.
 

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