Salt cell - fizzing or not?

[drewh]

Thanks James appreciate your help here. Yes it seems it is producing but how much is the question - the pool is blue and looking pretty good so it's enough for now. I'll test it & know for sure when the sacred TF-100 arrives (lol). These summer conditions here now are intense - left the cell off yesterday as I added salt so it could dissolve, and the pool started going slightly green already. But I added that liquid chlorine to 10ppm today as ping recommended so it'll be good tomorrow. Be good to accurately test CYA also (around 40 atm according top pool shop) then optimise it to the right level.

Re the DC current, the person from Crystal Clear who sounded fairly technical said it was a half wave rectified, not smoothed signal so he felt it would get a reading on an AC clamp meter. Would you have tried measuring this type of source using an AC amps clamp to see how close it is? Assuming the missing negative swing is ignored, then the clamp meter should read approx the current at the half rectified peaks shouldn't it? Today it was reading 16.5A, but the reading is very consistent.

Re the transformer interference, so it could provide harmonics etc. that threw it off? To me it just seems the 14/16A sounds about right given 30A rated when new.

Prob fighting a losing battle with this but still really interesting to think it all through.

 

[ping]

I'm more confident that you were having a nascent algae bloom and the SWG could just make enough chlorine to prevent it from blooming since the pool turned green on you with the SWG off for a day.

Before you adjust the CYA to 80 ppm, you need to SLAM the pool when you get the test kit. It will be easier to SLAM with a lower CYA level. Read up on the SLAM process, a one time addition of chlorine is not going to kill off all the algae.

 

[drewh]

I'm more confident that you were having a nascent algae bloom and the SWG could just make enough chlorine to prevent it from blooming since the pool turned green on you with the SWG off for a day.

Before you adjust the CYA to 80 ppm, you need to SLAM the pool when you get the test kit. It will be easier to SLAM with a lower CYA level. Read up on the SLAM process, a one time addition of chlorine is not going to kill off all the algae.

Totally agree ping, didn't think of it that way - SWG was just keeping it at bay. Good test really in the end! These are the most testing conditions for the pool also as its been really hot here of late (32 deg today, 39 and 40 on Sat/Sun!).

Yes I know re easier with a lower CYA, I held off changing it at all until I got the kit and could do the SLAM. Hopefully I'll get rid of that black algae (re other thread) and will maintain it. Actually really looking forward to tackling that. TNT hurry up!

 

[JamesW]

For testing AC where the load is non-liner, a true RMS meter is needed to get an accurate current reading. On the DC side, a DC capable meter is required to get a good reading. I don't know enough about how the meter works to know if the reading is good using an AC meter.

 

[drewh]

Hi James didn't realize I hadn't replied to this. What I'll try and do is borrow a DC clamp meter and try both to see how close the AC was. Prob not really possible to know any other way. I have an oscilloscope my dad used to use but not sure if they can handle 30A (or around the 16 it's drawing if accurate)... owise could see the actual waveform.

 

[JayBauman]

For testing AC where the load is non-liner, a true RMS meter is needed to get an accurate current reading. On the DC side, a DC capable meter is required to get a good reading. I don't know enough about how the meter works to know if the reading is good using an AC meter.

This isn't easy to measure. Due to the electronic losses in your transformer when converting from AC to rectified half wave, there will be a resulting DC component and a half wave "AC" component. A DC voltmeter could measure the DC signal, but it might not be the DC signal you are interested in measuring. The magnitude of the half-wave AC component will be somewhat smaller magnitude than the full AC input. The only numbers you really care about are the DC voltage and DC current delivered to the plates, as this is what drives the oxidation of chloride into chlorine. Can you measure these values?