Rainbow 320 - Slow Dissolve

[sugast]

I've been working this issue for a couple of weeks. The 3 inch tabs are dissolving very slowly. I've replaced the check valve, o-rings, back-washed the filter, etc. I also inspected the canister screen/filter at the bottom of the canister. It's not clogged. The pump runs on high speed from 6AM - 8AM and 4PM - 6PM daily. It also runs on low speed from 11PM - 3AM daily. With this schedule, it's only dissolving 1 tab in a week.

Pump on high Speed

Pump on low speed

I've included a couple of videos to demonstrate water flow. Is this normal?

 

[ajw22]

Yes, this is normal. Run your pump at high speed for longer to get more out of your tablet chlorinator.

Beware of the amount of CYA that will accumulate in the water with constant tablet use.

 

[HermanTX]

Based on your videos, there is flow only into the puck canister when running pump at high speed (what is that speed?) which is only 4 hrs per day (2 in morning and 2 in afternoon). Probably not sufficient flow to dissolve more.
Can you find a speed that is between the 2 you have now that flows through the puck canister? Then run that for 8 hrs a day (for example). If you feel the puck canister is working properly - you have checked or changed out most of the parts. So you need more time with flow through the canister to dissolve the pucks. The goal would be to run at the lowest rpm setting that flows through the puck canister and run that for a longer period during the day.

 

[sugast]

I guess I'll have to increase the high speed pump time. My pump is only two speeds. Th weird thing is it used to dissolve tabs much faster and maintain higher chlorine levels. I realize my CYA is now in the 45-50 range as opposed to the high 80's + so the UV is eating much more chlorine now. I did an OCL to confirm I don't have algae. With the dial on 5, my FC levels barely stabilize between 3 and 3.5. it used to easily get in the high single digits. My PB told me the ideal CYA level in Dallas is 70 - 80. That seems high to me and I just did a refill to lower the CYA from the 100+ range! Thanks guys!

 

[HermanTX]

You should consider switching to liquid chlorine (LC) since you are at 50 CYA. The LC will be more effective quicker and won't add to the CYA value. It is a little more effort to add LC every day but IMO, the benefits out weigh the effort.
Plus you can turn off that chlorinator. Also, never add LC into the chlorinator - always add LC directly in front of a return jet in the pool or spa.