Weak chlrorine production from new Hayward T-15 Cell

[clarity1000]

Last summer I replaced my Hayward T-15 cell for a new one. The old cell, before it failed, consistently produced between 4 and 4.5 PPM. The new cell only produces 1 PPM of chlorine, both last year and this year, which seems to be cutting it close. My CYA levels are the same as last year. Here are my numbers:
FC 1.0
CC .2 (maybe less--1 drop)
Calcium 275
Alk 70
PH 7.6
CYA 30
Voltage 25.2
Watts 5.46
Salt 3100(per test 3200)
Percentage 85
Temp 73
Lights are ON and Generating
Pool run time : always 8 hours per day during daytime

I called Hayward Customer Service multiple times and they have told me the following:
1. Its my Phosphates. I bought a kit and tested them at 125, treated with PhosFree they are now 0 (zero). I disagreed
with this course of action but they insisted this is my problem. Still have 1PPM of chlorine
2. Now they are saying its my CYA. I told them the CYA level has been the same as when I was using the old cell which produced 4PPM. I will not increase
the CYA levels with a potentially defective SWG given the CYA/Chlorine tradeoff..
3. Now they are saying its my Nitrates---I don't know how to treat Nitrates.

My water is crystal clear and I never had one day of green/cloudy water. I have shocked the pool twice with bleach to 13PPM with less than 1PPM overnight FC loss. I am even testing the water at the pipe that enters the pool.

I hesitate to call customer service again since they always insist the SWG if fine and its the chemistry causing the lack of chlorine generation. I hesitate to shock the pool a third time but I will do what is necessary. ANY SUGGESTIONs on why this new cell can only produce 1 PPM vs. my old cell at 4 PPM.

 

[tackettaj]

I'm not an expert but based on what I've learned from TFP site your CYA is low. You're overnight chlorine test shows you're not losing it overnight so it's being pulled out of the pool by UV. Stabalizer will bring your CYA up and keep the sun from stealing all of your chlorine and you should be able to get your levels up and then maintain. I follow the Chlorine/CYA chart and for a SWG pool you should be much higher.

 

[Richard320]

Easy way to tell if it's working. When the light is on and it shows it's generating, plunge a big cup or pitcher or something upside down in front of the return and then turn it sideways so the return jet fills it with water straight out of the jet. Let it flush a while and then bring it up and test that. If it's higher than the average pool water, it's working.

If it's working, something's using it up. Two things consume chlorine: sunlight and organics. Eliminate sunlight by manually adding bleach to the pool to get it up around 10 FC and performing an overnight loss test. If you don't lose any chlorine after dark, it's sunlight and you need more CYA. If you DO lose chlorine in the dark, you have an algae bloom starting and the SWG can't keep up with the demand. In which case you need to SLAM. And since you already jacked the FC up the night before, it should be easy to raise it up again to shock level.

 

[Saturn94]

Easy way to tell if it's working. When the light is on and it shows it's generating, plunge a big cup or pitcher or something upside down in front of the return and then turn it sideways so the return jet fills it with water straight out of the jet. Let it flush a while and then bring it up and test that. If it's higher than the average pool water, it's working.

If it's working, something's using it up. Two things consume chlorine: sunlight and organics. Eliminate sunlight by manually adding bleach to the pool to get it up around 10 FC and performing an overnight loss test. If you don't lose any chlorine after dark, it's sunlight and you need more CYA. If you DO lose chlorine in the dark, you have an algae bloom starting and the SWG can't keep up with the demand. In which case you need to SLAM. And since you already jacked the FC up the night before, it should be easy to raise it up again to shock level.

I would add that when doing the OCLT, run the pump/filter (SWCG should be off) overnight to rule out the possibility something in the filter is eating up chlorine while the system is running.

 

[tim5055]

Can I assume Atlantic Highlands is in NJ on the beach? Lots of sun?

My bet is you are loosing a lot to the sun.

Run the tests Richard suggested and I think you will find your cause.

Plus, the T-15 is just a little undersized per our recomendations. It's a 40,000 gallon unit and we normally recommend doubling the size of your pool for sizing the SWCG.

 

[DaninFLA]

you got good recommendations here. I think your problem is too low of CYA. I would increase that to 60-80 per recommended levels for SW pools.

secondly, I would manually dose chlorine to get to your target FC, then fine tune your SWCG to maintain that FC level. with your unit not being oversized, its going to be a challenge to increase your FC, but it should do fine at maintaining.

and I would stop calling Hayward, they are giving you bad advice. nitrates? lol.

you got an undersized unit for your pool and its struggling to keep up. up the CYA to help it and manually dose to get it to where it should be

how many hours you running the pump/generator?

 

[clarity1000]

Thank you everyone for your quick responses. Since I'm not losing any FC overnight, I guess the CYA level has to be the culprit. It has always been low, yet the old cell seemed to keep it maintained at about 4PPM. I guess I'll increase the CYA levels to 60 PPM and see if it improves. I'll bring the levels up to 4 PPM with bleach. BTW---The pool gets a lot of shade during the day due to trees and a two story guest house that blocks some sun. Not many people use the pool either.