is 30g sump enough for 250g tank?
- Thread starter ailachami
- Start date
I agree, bio filtration will be OK but if the pump shuts off overflow will be an issue. Look for a 55G or go with a 50G Rubermaid storage container. I am currently using 2 of the rubbermaids on a 315G.
It can be done, but too much risk if the pump shuts off, I like badoleross's idea. Cheap but effective
The truth of if it can be done boils down to two things.
How low can you run the sump without the pump sucking air.
How much your tank level drops when the system is off.
If you can get the sump to run at a low water level and get the tank to barely drop when the pump is off, then you can run a smaller sump. However it will take a lot of work and may not be worth it.
I have 55 gallon on my 220, I have spent a lot of time getting the system where the sump can run at a low water level like 4 inches. The problem I face is the level the tank drops which is about 2 inch.
How low can you run the sump without the pump sucking air.
How much your tank level drops when the system is off.
If you can get the sump to run at a low water level and get the tank to barely drop when the pump is off, then you can run a smaller sump. However it will take a lot of work and may not be worth it.
I have 55 gallon on my 220, I have spent a lot of time getting the system where the sump can run at a low water level like 4 inches. The problem I face is the level the tank drops which is about 2 inch.
keep in mind, for every inch in height in an 8x2 foot print tank is 30 gallon of water. your overflow will needs 1/4" or more (as much as 1") for flow from tank to sump depends on the pump and size of overflow box/area. your w/d will need 6" min to operates. I use a 80 for my 270..with 20 gallon bioballs, 20 pounds of ceramics ring and still adding more media. the pump is 3600 gph but valved down to 2500gph because it overflows the overflow boxes ( i did try to drilled the teeth to make them wider but only helps little). Using the 30 gallon in a 250 is asking for a flood.
I think it depends on a few things:
1) Shape of the sump. If the tank being used for the sump is tall, then it helps.
2) Plumbing from and to main tank. The longer and/or wider the plumbing, the more water that needs to be pumped out of the sump, therefore, may lower the sump water too much. This is where #1 helps.
3) Volume taken up non-water in the sump. As someone earlier said, having bio-balls, filter media, etc. takes up volume in the sump, thus, leaving you with less volume of water.
4) Sump design. If you have the a dedicated chamber where the pump sits and water overflows into it from a neighboring chamber (example), then you'll have less water volume to work with.
If you do decide on the 30 gallon, with everything installed but pump off, fill up the main tank until it starts to overflow into the sump. Then fill up the sump to desired level. Turn on the pump and watch the water level in the sump. If the sump water level gets too low where the pump is sucking air, then you need a bigger sump. If it doesn't get too low then you should be fine. Just be mindful that the water tends to evaporate quickly so don't let the water level get so low that the pump sucks in air.
1) Shape of the sump. If the tank being used for the sump is tall, then it helps.
2) Plumbing from and to main tank. The longer and/or wider the plumbing, the more water that needs to be pumped out of the sump, therefore, may lower the sump water too much. This is where #1 helps.
3) Volume taken up non-water in the sump. As someone earlier said, having bio-balls, filter media, etc. takes up volume in the sump, thus, leaving you with less volume of water.
4) Sump design. If you have the a dedicated chamber where the pump sits and water overflows into it from a neighboring chamber (example), then you'll have less water volume to work with.
If you do decide on the 30 gallon, with everything installed but pump off, fill up the main tank until it starts to overflow into the sump. Then fill up the sump to desired level. Turn on the pump and watch the water level in the sump. If the sump water level gets too low where the pump is sucking air, then you need a bigger sump. If it doesn't get too low then you should be fine. Just be mindful that the water tends to evaporate quickly so don't let the water level get so low that the pump sucks in air.
