Salt cell - fizzing or not?

[drewh]

Hi all,

The salt cell in my pool looks like it could be on its last legs - the last few weeks testing chlorine using my basic DPD test kit it has been around 1/1.50ppm (chlorinator running 6 hours a day), I'm getting a TF-100 kit sent here to Aus soon so will be able to accurately measure it.

I was reading some comments that the cell should fizz/have a reaction as the water is going through it and also the colour of the water should be different than just clear. With my cell, there definitely doesn't seem to be any sort of fizzing reaction (fizzing could be the wrong word) and the water appears clear. However, calcium definitely builds up on the plates quite a lot - so is that a sign of how well it's working?

Last season it was consistently maintaining about 8ppm according to weekly pool shop tests (I know!) but that was very consistent. So strange it would drop down so much if that is accurate. The pool is nice and blue though, my CYA according to the pool tests is about 40 (will know for sure as soon as the TF-100 arrives... can't wait).

 

[pooladdict]

If you can check diagnostics that would give you a better idea. Just how old is this cell. The calcium could be telling you to clean it, that might give it some more.

 

[drewh]

If you can check diagnostics that would give you a better idea. Just how old is this cell. The calcium could be telling you to clean it, that might give it some more.

When you say check diagnostics how do you mean? Cell would be almost 5 years this calendar year/season. Just curious whether it not fizzing could mean it's almost gone (but because it's building calcium on plates obv it is working). I usually clean the cell every 2/3 weeks in dilute MA, am keeping the pH lower to reduce the calcium buildup as my pool has higher CH.

 

[pooladdict]

I am not familiar with Crystal Clear SWG, but some brands have diagnostics for owners to verify all power readings are correct. 5 years if running all year could mean the cell is on its final legs.

 

[JamesW]

In your signature, you have 7v dc / 30 amp. Did you mean 30 v dc / 7 amp? If you can check the voltage and current, that would tell you if it's working. You should be able to see chlorine gas and hydrogen gas being produced at the plates if you have a clear cell. You should be able to see hydrogen gas coming out at the returns when it's generating. You should get a higher chlorine level from water coming out of the returns than in the bulk pool water.

Note that the system cycles on and off depending on the swg setting. If you're testing during an off cycle, then you won't see any indication of chlorine production.

 

[drewh]

I am not familiar with Crystal Clear SWG, but some brands have diagnostics for owners to verify all power readings are correct. 5 years if running all year could mean the cell is on its final legs.

This one doesn't have digital diagnostics like some units. It has a salt monitor / chlorine production gauge, see pic. It usually sits around the LOW mark but has been there for 2+ years inc last year where FC was maintained at 8ppm.

In your signature, you have 7v dc / 30 amp. Did you mean 30 v dc / 7 amp? If you can check the voltage and current, that would tell you if it's working...

No it's 7V DC / 30 amps (there are even 40A and 50A models here in Aus).

Could I put a multimeter between one side of the circuit (ie Chlor unit -> multimeter -> lead to cell) to see what the actual current draw is? I'd imagine it'd be quite low if it's almost gone.

I've never really seen hydrogen or chlorine gas in the cell or returns. I did test the water right at the eyeball returns and it only had slightly higher chlorine (maybe 3ppm).

 

[JamesW]

Does the production indicator needle go into the green? What is your salt level?

 

[drewh]

Does the production indicator needle go into the green? What is your salt level?

Yes it does, just. But has been the same position for 2+ years.

Salt level is about 3700ppm tested just over 2 weeks ago.

 

[JamesW]

I'm not familiar with that swg. I will try to find out more. If the water at the returns is higher in chlorine, then it is working.

Most multimeters can't handle 30 amps directly. You could use a clamp type ammeter if you can rig up test wires that would allow you to clamp around only one wire.

Note: Don't do anything that you are not sure you can do safely.

 

[ping]

I suggest bumping up the chlorine level to 10 ppm using bleach to help the SWG out a bit. You are coming out of winter, and I have a feeling there is some nascent algae in the water that the SWG is just preventing from blooming. When you receive the TF-100 test kit you will be able to an OCLT and confirm if there are any organics in the water. Since you do get a higher chlorine reading from the return water I have a feeling the SWG is running fine but there are some organics and the SWG just can not get ahead of.

 

[JamesW]

The manual has some troubleshooting tips. Have you reviewed the manual?

http://www.crystalclearchlorinators...ors-STD-units-Operating-Manual-PDF-Format.pdf

Where did you find the current and voltage specs?

 

[pwrstrk]

May also be low CYA level and the sun is burning the FC off and your SWG isn't keeping up. We recommend the CYA level be 70-80 for a SWG.
When your get your kit do the OCLT Test like ping suggested to rule out organics or not. Test your CYA level also.
Keep us posted ! ?

 

[drewh]

So much great advice, thanks heaps.

Most multimeters can't handle 30 amps directly. You could use a clamp type ammeter if you can rig up test wires that would allow you to clamp around only one wire.

Thanks James, I have used mm's often in the past but yes true it would exceed the max 10A, I've rarely ever measured current to be honest. I actually have a DC clamp meter so could try that - I could get it around just the phase wire, will try that this afternoon.

I suggest bumping up the chlorine level to 10 ppm using bleach to help the SWG out a bit. You are coming out of winter, and I have a feeling there is some nascent algae in the water that the SWG is just preventing from blooming. When you receive the TF-100 test kit you will be able to an OCLT and confirm if there are any organics in the water. Since you do get a higher chlorine reading from the return water I have a feeling the SWG is running fine but there are some organics and the SWG just can not get ahead of.

Thanks ping, it was higher at the returns but not massively so (will measure accurately when he TF-100 arrives). Great suggestion re adding chlorine to give it a hand - I have had that other algae spreading (black in colour but brushes away) re the other thread, so it could be fighting that. Though it was there last season but still a possibility. I'll do the OCLT test also and know for sure.

 

[drewh]

The manual has some troubleshooting tips. Have you reviewed the manual?

http://www.crystalclearchlorinators...ors-STD-units-Operating-Manual-PDF-Format.pdf

Where did you find the current and voltage specs?

Thanks James, I did look at the manual that came with it but it was very short & not helpful at all. This online version is more detailed.. go figure. (didn't occur to me to look it up online!).

See the pic for the current & voltage specs on the unit itself.

 

[drewh]

When your get your kit do the OCLT Test like ping suggested to rule out organics or not. Test your CYA level also.
Keep us posted ! ?

Thanks pwrstrk I will do that - v keen to get the kit! I didn't want to add any CYA till I knew accurately what it was. Pool shop shows about 40 now. Also because of the algae, wanted to keep it a little lower till I've SLAMed the pool to get rid of it, as I'd need to use more chlorine owise.

 

[drewh]

Just used my clamp meter to check the current being drawn. The cell is drawing about 14.5/15A. So about half the rated 30A. That doesn't sound too bad?

 

[JamesW]

If the voltage to the cell is good, then it is making chlorine. I'm not sure if that current is considered within specifications or not. Perhaps a call or email to the manufacturer would be worthwhile.

 

[JamesW]

Also, check that your multimeter will do dc current. Some clamp type multimeters only do AC. If yours only does AC, you can do a current check on the AC supply side. It should be between about 0.7 to 1 amp.

 

[drewh]

Hey James, funny you say that re dc current. I measured it with my clamp meter (ac only) but forgot it couldn't do dc till after. The weird thing is, it gave a very clear reading - rose from 0 very steadily as the cell filled with water and ended up around 14.5/15A. I'm thinking the power unit would just have half/full wave rectification so maybe the ac clamp can measure the peaks? I don't want to blow $120 on a dc clamp meter just for this though. I measured the supply side and it came out at 1.06A. What do you think?

UPDATE - heard back from Crystal Clear chlorinators, the guy said the power unit produces half wave rectified DC that is not smoothed, so this would give a reading on an ac clamps meter. So the 14.5 would be correct then?

 

[JamesW]

Based on the higher chlorine at the returns, the production indicator, and the current readings, I think that the unit is probably producing some chlorine. Whether or not it's producing at full output is hard to determine.

Five years is about when many cells begin to decline in output capacity.

The DC current won't be accurate if the meter is only designed for AC current. I have tried measuring DC current with my meter set to AC current and it read about 75 % of the actual current. It's a true RMS meter, so that might make it more accurate, but I'm not sure. I don't know how much value the AC meter reading has, in general.

The AC current might not be accurate if your meter is not designed for the frequency. The unit appears to be 50 Hz. I would think that Multimeters sold in Australia would be designed for 50 Hz.

Another issue with measuring AC current is that the power is going through a transformer, which can have an apparent current different from the real current.

The measure the actual power used by the unit, you would need a wattmeter designed to measure power where the frequency is not a clean sine wave of the specified frequency.