Trying to regulate the sump water level in RSM 500

Chicosdad

New Member
Hi,
I have had my used RS 500 setup for a little over 10 days.
I have the tank water level at the correct height but I am having trouble keeping the sump level at the correct height- it keeps wanting to fall below the 2 lines. It's still high enough for the skimmer and return pump to work, but it's still low. I think some drop is due to evaporation, but the salinity has been very stable at 1.023/1.024, there for I haven't added RODI water from the ato.

The pump that came with it is a variable speed pump, so I have tried to lower the speed so the sump tank stays at a higher level.
Any suggestions on what I am doing wrong? I have adjusted the gate valve so operations are quiet.

Thanks for your help.
 

Nobbygas

Well-Known Member
If the tank level is ok, but the Sump level is dropping, this suggests that your ATO isn't working. As long as you have RODI water in the back chamber, the ATO will ensure the levels remain constant.
Every time you adjust the return pump flow rate, you will have to adjust the gate valve. Find the speed you want the return pump to run and stick with it as it will become a PITA to constantly adjust the gate valve.
"there for I haven't added RODI water from the ato." - This comment. The ATO should be adding the RODI water not you!
 
Last edited:

DreRSM500

New Member
Hi,
I have had my used RS 500 setup for a little over 10 days.
I have the tank water level at the correct height but I am having trouble keeping the sump level at the correct height- it keeps wanting to fall below the 2 lines. It's still high enough for the skimmer and return pump to work, but it's still low. I think some drop is due to evaporation, but the salinity has been very stable at 1.023/1.024, there for I haven't added RODI water from the ato.

The pump that came with it is a variable speed pump, so I have tried to lower the speed so the sump tank stays at a higher level.
Any suggestions on what I am doing wrong? I have adjusted the gate valve so operations are quiet.

Thanks for your help.
I also just setup a pre-owned RSM500. Ive been doing a lot of research and its pretty much cycling right now. Referring to the owners manual, and what ive experienced so far the sump level under the tank does not correlate to the water level in rear of display tank. I found that my sump level under tank i set my the initial a mount of water I put in or take out. The gate valve is extremely sensitive, so I just open it all the way and every 20 secs adjust little by little until water behind display tank is at the second line. 20220420_081207.jpg
 
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