SWC high salt when solar turned on

[mas985]

Thanks Sean,

I didn't think about the temperature causing the problem. I know the conductivity of water goes up with temperature but I thought it was less than 10% change over 100 degrees. Perhaps they are using the temperature in the salt ppm calculation and that is where the error arises from.

Pat,

Mine has a flow switch as well but always seem to indicate a flow so there must be enough water with the air to keep the switch closed or the air rushing by it is sufficient.

One more thing, when I watch the salt level, it does not seem to rise until after the air is purged from the panels.

[waterbear]

I am sure it is the temperature as Poolsean said. I have an Aqualogic PS-8 and it controls my pool and spa separately. I know the salt concentration in both is the same (I run the spillover when adjusting chemicals and check salt levels in each with both chemical tests and a handheld and calibrated salt meter) but my spa constantly show a higher salt concentration than my pool on the Aqualogic control panel (usually about 200ppm higher). The only difference is my pool is at 82 deg and the spa at 104!

[PatL34]

Mark,

You mention that there is sufficient flow with the pool water/air mixture to keep the flow switch on. If this is correct than you have the potential to create a hydrogen/air mixture which could be explosive. I am not kidding. Any system of this sort has to have that protection to shut off regardless of who made it. Hydrogen can be very unpredictable in the presence of oxygen. In other words been there, seen it happen. You just do not fool around with hydrogen in the presence of anybody.

Pat

[Poolsean]

Pat,

I'm very certain that mas' high salt problem is due to the increased water temperature. I've seen it over and over again. There is no increased concentration of salt in the solar panel when it is off. It's the increased temperature.
Solar panels should not drain down when the pump shuts off, therefore there should not be a period of air cycling through the system to cause the hydrogen/oxygen condition you're cautioning about. This is mostly a problem when there is a failed flow switch and the cell is saturated in water, but not for intermittent air pockets passing through the cell.

[PatL34]

Sean,

The feeling I get is that the PoolPilot protects and recovers from a water/air mixture better than the Autologic by virtue of the low salt reading and low flow reading, delaying the power to the cell until things are normal. That's what I am trying to get at.

Pat

[mas985]

There are really two conditions when this happens.

1) When the pump first turns on in the morning, 11am, there is air in the solar panels and the flow switch does turn off as the air pass through the cell so that does seem to work ok. Given that there is no water in the panels, at least that I know of, the only explaination for the high salt in this condition is that the water is very hot going through the cell. I will verify this later when I heat up my spa to see how much the salt reading changes.

2) After the panels have been on for a while and then turned off due to a cloud or wind and then turned on again later, there is very little if no air in the system so that is why I did not see the no flow indicator or I think I might have missed it. High salt comes on in this condition as well.

I was thinking at first of condition #2, so that is why I thought that the salinity was changing in the panel. However, condition #1 would not happen if it was just the salinity, unless water or salt was left in the panel. That is probably unlikely.

Therefore, as Sean orginally pointed out, temperature is probably the culprit. I am still looking for a good reference relating temperature, salinity and conductivity.

[mas985]

Well, a very interesting development. I did a couple of experiments and got the following results.

Put the spa on solar starting at about 90 degress and a salt level of 3200. Ran the cell temp up to 105 degrees but the salt level did not change at all, still 3200. The controller must do some compensation for temperature.

Next, I turned the valves to spa spillover without solar and waited 10 minutes for the panels to really heat up. Turned them on and I saw the temperature, salt level and amps all rise together until the temp hit 108 and salt hit 3700 and the warning came on. I immediately reset the cell and there is a 15 sec delay before coming on again. When it came on, the temp was still 108 but the salt level was down at 3200. I watched as the temp lowered but the salt level did not change.

I repeated the above again but after 20 min and got a slightly different result. The temp did not rise as quickly but the salt level did. It hit 3700 ppm when the temp was only 92 degrees. This makes me think it is a salinity issue and not temperature.

If temperature is causing the problem, it may be that the controller cannot compensate fast enough for a fast rise in temperature or even display it correctly.

[waterbear]

There are really two conditions when this happens.

1) When the pump first turns on in the morning, 11am, there is air in the solar panels and the flow switch does turn off as the air pass through the cell so that does seem to work ok. Given that there is no water in the panels, at least that I know of, the only explaination for the high salt in this condition is that the water is very hot going through the cell. I will verify this later when I heat up my spa to see how much the salt reading changes.

2) After the panels have been on for a while and then turned off due to a cloud or wind and then turned on again later, there is very little if no air in the system so that is why I did not see the no flow indicator or I think I might have missed it. High salt comes on in this condition as well.

I was thinking at first of condition #2, so that is why I thought that the salinity was changing in the panel. However, condition #1 would not happen if it was just the salinity, unless water or salt was left in the panel. That is probably unlikely.

Therefore, as Sean orginally pointed out, temperature is probably the culprit. I am still looking for a good reference relating temperature, salinity and conductivity.

Perhaps a call to Goldline Tech support is in order. I have found them to be very good at answering questions!

[mas985]

Thanks waterbear

I did call them and they said that the cell can only handle water temperatures less than 104 degrees. If the water temp exceeds that, the cell will read high salt/amps. Also, she said that it should reset fairly quickly which I have not confirmed. Next time it happens, I will see how long it takes to reset.

So Sean was right after all.