Modified ASM G3 Skimmer Intake Pump Replacement Question

[JohnV8r]

I have an ASM G3 that I have done the mesh, gate valve, and recirc mods to. I have used a MaxiJet 900 for the intake pump. Performance has been great. The dwell time created by the recirc mod (doubles the volume of aerated water in the skimmer body) and reducing the input from 500 gph (original Sedra 5000 spec) to approximately 230 gph (MaxiJet 900 spec) has helped to really increase the quality and amount of skimmate produced.

However, recently I have begun to encounter some input reliability issues with the MaxiJet. I get the skimmer all dialed in and after a day or two of running fine, the input vacillates and overflows the skimmer cup. That in turn causes the skimmate to be released back into my system - obviously not a good thing.

Also, it's not a change in sump water level as I have an ATO that keeps the water level steady.

I have attributed the vacillation in input to the age of the MaxiJet and I am going to replace it. I am considering replacing the MaxiJet with either a Sedra 3500 or an Eheim 1250. Both pumps deliver 320-350 gph at a wattage draw of 28-35 watts. That will keep the heat transfer low. Net volume of water in my system is 194 gallons, so 320-350 gph keeps me in the dwell time range I am looking for.

Here's my question and what will ultimately drive which pump I use: Would there be a benefit to having the input water going into a recirculating skimmer (the recirc aerates the input water during recirculation) aerated by a needle wheel and venturi during the input?

I know that boring a venturi on a Sedra pump to increase the air to water mixture actually decreases performance. However, does inputting additional aerated water that has the proper air/water ratio for good skimming alter performance?

If no, I'll likely go with the Sedra pump and aerate the input water. If yes, I'll go with the Eheim and not aerate the water.

Thanks in advance!

 

[sirreal63]

I did this with a GenX NW pump, it has it's set of issues, first off, when salt creep clogs or begins to restrict the air intake of the feed pump, the water level will rise in the skimmer and cause it to overflow. Secondly, the Sedra 5000, if in good working order, puts just about the perfect amount of air into the G3 body. My G3 is also recirc'd with the gate valve and I have tried numerous pumps over the years, and nothing has worked as well as the 5000. Change the feed pump, but keep in mind that adding air via the feed pump will not solve your issue, it will create it as well. I am still using the GenX to feed mine, but without the venturi hooked up.

FWIW the sump water level has virtually no effect on the water level in the skimmer, one of the main reasons I prefer a recirc, I run no baffles in my sump. I would replace the MJ900 and not fool with anything else.