Replace T-CELL-3 with CL-100?

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R

rjg45

0
Apr 16, 2016
7
Phoenix
Greetings. New member here. I have a dilemma:
I have a 11,000 gal pebble pool/spa with T-Cell-3 generator that has failed. Every 3-4 years I need a new one. I may also have to replace the system board due to new firmware required for the new cells... And also need a new flow sensor since the cable has come apart. So it will be expensive. I like salt cell however my water has a very high pH on this system. This has required lots of acid. The only way I can keep the pH normal is to add acid daily. If I add too much in one shot it degrades the grout in the natural stone waterfall between the spa and the pool making a cloudy sediment. And the cell requires frequent cleaning with acid to clear out the scale. High maintenance.

However - in the interim I've been using a floater with jumbo tabs. I like the tabs because amazingly I don't have to add acid. The pH is perfect. And just had the water tested and all readings were excellent. So, my dilemma is whether to stick with the T-cell and struggle with the pH and constant maintenance or just replace the t-cell with a Hayward inline Cl-100? To make a long story short, it's been 3 years with the floater and the downside with that seems to be some staining on the natural stone.
Thanks!
 
:wave: Welcome to TFP!!!

It is fairly normal to have to add acid to lower the pH when using a SWG until your TA is inline. What TA were you maintaining? Also aeration of the spill over from the spa to pool will also drive up the pH.

If you were correctly monitoring your pH and adding only the acid required to keep it balanced, then this would not have any affect on your stone.

If you have high CH (likely given location) and let your pH get too high (you admitted as much), that is what causes the SWG cell to scale up. Better balancing and this is not a problem.

The tablets are acidic, thus why the pH is not rising, but they are constantly adding CYA which builds up in the pool. The higher the CYA, the higher you must maintain the FC to sanitize the pool and keep algae away. The acidic nature of the tablets in a floater sitting against the pool side could certainly cause prolems with the grout.

My guess is that your CYA and CH are so high right now that you need water replacement to take control.
And if you want to take control, you need to have a good test kit and post up a full set of test results ... don't bother with pool store testing, we don't trust it.
 
Hi Jason, and thank you for the reply.
I did have the water tested at Leslie's last week (I know :(). Here were the results:
FAC 3; TAC 3; CH 200; CYA 60; TA 80; pH 7.6; Cu 0; Iron 0; Pho 300;
I have a k2006 test kit and will confirm the Leslie's results. We just moved back into the house after 5 years. During that time the pool was maintained by a pool service person. Now I'll be maintaining it myself as I had in the past. Since that time the salt cell died and the service man switched it to the floater. Which seems to have been good from what I can tell. Ok, thanks again and I will confirm the water test soon. :D
 
I tested myself and got the following results:
FAC 5; TAC 5; CH 380; CYA 100; TA 90; pH 7.4; Sat. Ind: 0.6;

Chlorine is high because of a new tablet and also shocked it a few days back for what I thought was algae but probably just dirt. Brushed it all off and it is gone now. So, my feeling is that the tablets mean less overall maintenance but I guess I will watch it more closely for while and see what happens before re-investing in the new SWG. :)
 
What are you testing with? That appears to be missing the extremely important FAS-DPD chlorine test.

Your CYA is way too high and your FC is actually way too low for that CYA level. The tablets are just adding more and more CYA and you are heading toward an algae bloom if you already see it.

You need a better test kit, replace a lot of water, and then to follow the SLAM process.
 
In AZ sun without saltwater you will want your CYA to be 50-60. With saltwater you will want it to be 80. Then chlorinate your pool to target level based on this, Chlorine CYA Chart

Each 8oz trichlor puck adds 2.2 ppm chlorine and 1.6 ppm CYA.
 
Thanks to all for your replies.
Jason, I use the powder for the test with the K2006 test kit and also have an OTO tester as well.
My nomenclature is wrong, sorry about that (learning has occurred - thank you TFP forums!). Tested again just now and free chlorine is 4.8 and combined chlorine is 0.2 or less.
Still debating on what to do here - whether to go back to the SWG and the near daily acid additions and the trouble that brings to my pool or to go with a liquidator. The LQ might be a good option for me since the pool is small (~11k gal.). In either case it seems I need to drain and refill. Perhaps my acid probs with the SWG were due to mismanaged TA (it has been a few years).
 

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A few things can contribute to PH rise
High TA, lower TA to 60 and see how that does, Pool School - Lower Total Alkalinity
Running waterfalls, bubblers, water features causes aeration which causes PH to rise. Running those less will reduce PH rise.
New plaster causes PH to rise for about a year

But, you really need to get your CYA figured out first.
 
After reading and learning more on this great forum, here is where I am on this.
My pool:
- pebble surface, 12 years old. (Phx area).
- spa is elevated above the pool, separated by a natural stone waterfall with very sandy aggregate grout.
- When the circulation system is on the spa spills over a natural stone waterfall into the pool. Can't turn that off.
- Aquarite SWG - currently not working. Need to replace T-CELL + flow sensor + maybe the PCB for new cell firmware compatibility (board is original).
- I'm on the jumbo tabs/pucks in the interim - works great except for high CYA

Things I dislike about the SWG in my pool:
- pH was constantly high: build up of that calcified white stuff in the T-CELL.
- Cell inspection and cleaning ~4x per year.
- Daily acid doses of about half a cup.
- T-CELL-3 needs replacing every 3 years or so. Maybe T-CELL-15 is better.
- System fragility: LEDs for low salt (calibration always grossly off), no flow, inspect cell, not generating for unspecified reason.

I became an expert at dealing with the fragility of the system but high pH bugs me the most. Not sure that even managing the TA closely will make things any better but have not tried that yet. I need to replace all my pieces parts and experiment with that. On the other hand, thinking of sticking with pucks: pH is great - w/o acid (I love that), maintenance is low, but CYA is high. So I change the water every other year - pretty simple. This one is sounding mighty attractive at this point :D.
 
LOL! Well, that is certainly one option. You likely have to drain some every few years to reduce CH as well. But, CYA will probably build up faster. If you use 3 ppm FC per day trichlor will add 1.9 ppm CYA, that will add about 57 ppm CYA per month.

You can reduce the amount and time of flow over your waterfall from your spa, many people do. It does not need to be at full flow the whole time and water does not have to be circulated through the spa the whole time you are filtering.

Controlling your CSI will eliminate, or significantly reduce, calcium build up inside your cell. Keep your CSI slightly negative, -0.1 to -0.2. My cell has not needed cleaning in 4 years. This will also eliminate scale build up and make your plaster last years longer. More here Pool School - Calcium Scaling. And here, Langelier and Calcite Saturation Indices (LSI and CSI).

Lowering your TA to 60 and adding borates will also reduce your PH rise and acid demand.
 
pooldv,
Thanks for the links and info. I'll give the SWG system another try, but first drain and refill and then manage it closely with the slam. In the meantime I'll investigate how to minimize the spillover from the spa to the pool when the system is running. Perhaps a removable siphon tube with a float valve. Have you heard of anything like that on the market? That may help with the pH.
 
Most folks either reduce the time that water circulates through the spa to 30 min/day or so and/or reduce the volume that flows by closing of the valve somewhat. Maybe set a timer to run the pool only for several hours and then run the water through the spa for 30 min to cycle it.
 
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