Skimmer size for DT or whole system? Plus flow question

Coach63 · Sep 3, 2015

Question-Everyone says get a larger (+1) skimmer for your system. Is that based on your DT (what is actually the source of the waste) or based on the total volume of the entire system? I am planning a 150 gallon DT but will have about a total system of 500 gallons with a large sump and an extra storage container for extra volume for stability.

Also, everyone says the more water turnover the better for SPS corals and most achieve this with large amounts of turnover through the sump and in-tank power heads. If your sump consists of a skimmer compartment and fuge compartment (which is better with slower flow) and your said skimmer only processes at 700 gph, why would you push so much water through your sump? Could you just run just above the skimmer load and increase your DT rate with larger / more power heads?

Thanks for your input.

Myka · Sep 3, 2015

You hit the nail on the head in your second paragraph. There is no need to have huge amounts of water going through the sump. 3-5x total system volume turnover through the sump is usually enough. Use powerheads to achieve the in-tank flow.

For sizing a skimmer, I keep a few things in mind. First, the brand of skimmer makes a big difference. Most manufacturers are optimistic about the skimmer's ability and over-rate them. Bubble King is the exception to this "rule". If you're buying a Bubble King, you can be satisfied that it will skimmer as Royal Exclusiv says it will.

Second, if the sump is overly large, or the skimmer is on a system where the total volume is much bigger than the display (like yours), then I consider this "extra" water that does need processing, but it's not the same as having to process that much volume with fish in it. What will be in all this "extra" volume? So my answer is yes, and no. Ha! Also, it makes a big difference too which type of corals you want to keep. If you want an SPS tank, then you will be best off with a very good skimmer that is also large compared to the volume.

Coach63 · Sep 3, 2015

Myka said:
You hit the nail on the head in your second paragraph. There is no need to have huge amounts of water going through the sump. 3-5x total system volume turnover through the sump is usually enough. Use powerheads to achieve the in-tank flow.

For sizing a skimmer, I keep a few things in mind. First, the brand of skimmer makes a big difference. Most manufacturers are optimistic about the skimmer's ability and over-rate them. Bubble King is the exception to this "rule". If you're buying a Bubble King, you can be satisfied that it will skimmer as Royal Exclusiv says it will. Second, if the sump is overly large, or the skimmer is on a system where the total volume is much bigger than the display (like yours), then I consider this "extra" water that does need processing, but it's not the same as having to process that much volume with fish in it. What will be in all this "extra" volume? So my answer is yes, and no. Ha! Also, it makes a big difference too which type of corals you want to keep. If you want an SPS tank, then you will be best off with a very good skimmer that is also large compared to the volume.

Thanks for the info: To answer your question about what is going to be in this "extra" volume, the answer is nothing. I have just researched and to add stability to your system, the easiest thing to do is add water volume. I was just going to get around a 300 gallon container and tie in a loop into the system to constantly turn over that volume of water into the system. Would you consider this "extra" volume to be say half the "skimmer load" volume to when it comes to choosing a skimmer? Meaning if I have a 150 gallon DT heavy bio load, you would want around a 250 gallon capacity skimmer (+1) when adding this extra water volume (say 350 with the container and sump) would you consider that to be say 125 gallon when sizing skimmer since it has no bio load added to the system? So combined you are looking at a system skimmer of around 375-400 gallons?