T cell 40 tests ok but not making chlorine??

I have Hayward goldline controls with a T cell 40 SWG and a upgraded intelliflo VS 3050 pump. I had the cell tested and it tests good. The controls are active at the set times and Voltage is around 26V. All water parameters test good with exception to chlorine. This problem seem to start after I upgraded from a single speed pump (1.5 HP @ 3450 RPM) to the Intelliflo. My pool is 25000 gal and I'm running the SWG 6 hours @ 65% which was fine with the old pump so I dont understand what would make a difference unless lower flow would cause a problem? I dont know where to look at this point? Ane experience with this would help.

Thanks

Hopefully our SWCG experts can advise you. Look for PoolSean, Waterbear and Waste.

Meantime you need to actively add bleach/liquid chlorine to your pool to prevent algae growth and keep your pool sanitary. The B-B-B method is 100% compatible with SWCGs.

Carl

Need a bit more info. Do you have any lights on the unit turning on or do you just not have any FC in the water? Please post a full set of test results for starters (include FC, CC, pH, TA, CH, CYA, and Salt). Have you increased your pump run time for when the pump is on low speed? Chlorine production is a function of output percentage (with a Goldline unit it means that your cell is on and generating for 65 minutes out of every 100 minute cycle for you 65% output percentage, then the cell reverses polarity and starts again) AND the pump run time so, for example, if you were running at 65% for 6 hours at 3450 rpm then you would need to run the pump for about 10-12 hours at 1800 rpm to maintain the same water turnover (but would have much lower electric costs which is the advantage of a multispeed pump AND you might have to turn the cell output down a bit for even more savings) SO, once again...
Have you increased the pump run time for the lower pump speed? Flow rate does play a part.

The green lights that are on are for pool/spa and filter which is normal. I havent had any error messages or red lights. It acts to be what I know as normal. The goldline equipment is now 4 years old.
Yes i increased run time from 8 hrs @ 3450 to 12 hrs @ 1750 and 2 hrs @2000 for the vacum,Total 14 hours.
TC=0, FC=0,CC=0,pH=7.9,TA=9.5,CH=470.Stabilizer (CYA)?90ppm, salt=2900ppm, additionally Nitrate=3, Nitrite=0,and Phosphate=200.

Thanks for your help.

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Also, since the chlorine levels have been zero, we have had algae blooms (small green spots). What we've read so far, it seems to be black algae. The finish is aggregate. How is the best way to treat this since we're having the chlorinator trouble? Thanks.

With a CYA of 95 and algae, you need to shock the pool up to about 25ppm and try and sustain that high cl level. 2 or 3 times a day, test the chlorine and each time, add enough plain household 6% bleach to get back up to 25. For now, go ahead and add 10 gallons of bleach which will get you to 25. For reference and to help you figure out how much to add each time you test, each gallon will add about 2.5ppm of chlorine.

BTW -- Your calcium hardness is pretty high. i would suggest not using any cal-hypo in your pool. When CH gets above 400, you often will start having issues with cloudy water especially if you also have high pH (which you do) and high TA. (You need to try the TA test again. A reading of 9.5 doesn't sound quite right.)

Run the pump 24/7 while you are trying to clear up the algae. When you get to the point where you can go from sundown one evening to within 2 hours of sunup the next day without losing more than 1ppm of cl, then the algae should be dead and you can let the cl level drift back down.

Sorry I can't help you with the problem with your cell, but hopefully in the meantime, this will help you clear up the algae.

After seeing your test results the first thing you need to do is add bleach to get the FC up to about 25 ppm to kill the algae. You need to keep adding bleach and brushing with a steel algae brush until you have killed the algae. Your test results look suspicious. TA of 9.5 just doesn't look right. Nitrate, nitrite and phosphate are really bogus tests designed to sell unneeded pool chemicals and the first two are rarely, if ever tested for. Are these from the pool store? If they are I would strongly suggest investing in a Taylor K-2006 test kit.
I would also check your cell for scaling and acid wash it. Your high pH and calcium hardness are a recipe for scale.

I suspect that your TA is too high. Your calcium at 450 is quite manageable but you need to get the TA down to about 70 ppm and keep your pH no higher than 7.8. When you lower it don't drop it lower than 7.6 since this will mean a slower pH rise in the long run. (pH rises faster the lower you put it.)
However, the first and foremost thing you need to concentrate on right now is killing the algae.

Sorry, TA=95. I miss typed it. Does the Taylor test kit go as high as 25ppm for chlorine? The kit I have currently only goes to 5ppm.

The K2006 or 2006C goes up to 50 ppm; that's one of the main reasons we recommend it. Another is that Taylor's phenol red continues to give fairly accurate pH test results up to 10 or 15 ppm of chlorine, vs 3 - 4 ppm chlorine from many other blends. If you already have a Taylor K2005, you can get *just* the FAS-DPD chlorine test; I think it's a K-1515.

Anyhow, links to Amazon for these items are found on the Amazon kit page in my signature. One caution: the Amazon seller, Amato Industries seems to be pretty consistently the cheapest and also more reliable than some others. We've seen some problems with other sellers shipping K2005 kits instead of K2006 models. Amato seems to restock in a day or two (they are located VERY close to Taylor), so if the link shows another seller, wait a day.

Thanks everyone, I,ll start with shocking and brushing and hopefully get my pool back. Do you think that the algae has been causing the drop in Chlorine? So far my equipment has tested ok and I've never had scale on the SWG plates.

Absolutely the drop in chlorine is due to the algae. That means it is doing what it is supposed to do ---- kill algae!

I suspect you may have some chlorine generation but it is being totally consumed by the algae. Get the mess cleaned up and stabilized with bleach and then watch for output from the generator. I'd start at 100% for the first couple of days after you get stabilized and then see if you can back it off
if the chlorine levels are good.