Chlorine and acid drum feeders

[max]

That sounds promising. The fixed component remains fixed and the higher CYA with the same FC/CYA ratio results in less loss.

My local pool shop's test which is better than mine showed CYA to be 60ppm a month ago - there has been little change in the water since so that is probably closer to the truth. Given the cover, I think 60ppm will do for which I'll find a SWG setting which results in lows of 3ppm (5%) rather than 1ppm.

Thanks for your help Richard.

Max.

[max]

Hi Richard,

I had another read of the Chemigem liquid feeder manual. You mentioned it may use a "rough proxy such as ORP" - that indeed is what the Chemigem uses. The default setting is 650mv. The manual says "For an ORP controller to work properly the pH, Total Dissolved Solids (TDS), stabiliser (iso cyanuric acid) and calcium hardness must be maintained within the recommended levels" which are:

• pH 7.2 to 7.8
• Total Disolved Solids (TDS) 300 to 1500 ppm or 1500 mg/l
• Stabilizer 30 to 50 ppm or 50 mg/l
• Calcium Hardness 90 to 300 ppm or 300 mg/l

"Chlorine and pool Acid will feed separately for a few seconds approximately every 3 minutes until the required levels are reached".

The comments I have seen regarding ORP in other threads are not favourable. If the feedback system is not that reliable, I don't see the point in them. Have you any comments on ORP?

Thanks,
Max.

[chem geek]

ORP can be useful as a feedback control system for the chlorine level, but one critical factor is that the pH be maintained at a constant level since ORP is very much affected by pH. The other parameters, such as CH and TDS, aren't as critical. Some sensors don't do very well measuring lower ORP levels associated with high CYA and lower FC, but generally you operate at a level that is reasonable for the sensor. So you should first accurately measure your FC and CYA and then note the ORP level and set the "setpoint" for that ORP level. That is, don't try and use the absolute ORP level to determine the amount of chlorine you should have.

ORP doesn't work so well in SWG pools due to the hydrogen gas generated from the SWG that interferes with the ORP reading, but the system you describe isn't for SWG pools as it doses chlorinating liquid or bleach instead.

[Guest]

So it now time to trash my ORP meter and get a test kit that measure free chlorines.

Thank all you guys for the good knowledges you share here

[Me...]

Well first off don't go trashing your ORP meter, they are very useful tools.

Second. Don't compare a SWG with no controller to a liquid feed one with a controller. Your chemical feed pump can be set similar to your SWG. There are dials on the face of the pump that allow you to control feed rates but you can also play with the chemical strength that it feeds, you can't do that with a SWG.

Either way a controller is something I always like to see used. ORP does seem to have an issue in salt pools and is no doubt why controlling the chlorine level appears to be more problematic than a non-salt pool. Some have said it is stray current that can blind the probe and cause false readings. I have put small current collectors on the flowcell lines to see if that helps, and at times it seemed to. Or go to isolated true PPM Sensors.

[in2thegarden]

I work for a botanical center, and we have a very special set-up. We have a mini-Mississippi river, that is essentially a wading pool for kids. I have an underground reservoir that hold about 3,800 gallons. We have a pump that moves the water from the reservoir to top of the river, where it flows through grates in the delta that drain back into the reservoir. Our river flows between perennial beds, and kids often add sticks, mulch, sand, other organic things found in a garden, to our water system.

We have a Chemtrol ORP and pH reader, and use acid and liquid chlorine auto-injectors to sanitize the water. I am having a difficult time balancing a good ORP level with a FC level that is within state standards of 2-4. The mechanicals add CL to clean the water, but then FC levels are too high. What other steps can I take to help the ORP be higher without too high FC levels?

[sammantrao]

hi guys,

i wanted to know if basic garden water timer can be used to dispense chlorine. I wanted to know if the plastic of will withstand liquid chlorine coming out of it and for how long.