Skimmers: Oversized or Undersized?

reefinginBD · Sep 3, 2023

I'm setting up a 150 gallon mixed reef tank and I'm currently debating on whether I should go with the Bubble Magus Curve 9 Elite or the Bubble Magus Curve 7 Elite.
I will have around 25-30 fish with 6-8 of them being on the bigger side. I'll feed the fish with pellets and occasionally feed nori to the tangs. For mechanical filtration, I will have two 4-inch filter socks. The tank will be a mixed reef with a mix of all the different types of corals. Water changes will be done bi-weekly or as needed. I do not want to oversize the skimmer too much but also do not want to undersize it. So, which sized skimmer should I go with? Do let me know! Thanks in advance!

exnisstech · Sep 3, 2023

I can't recomend which skimmer but I will say in this hobby as many things too much is better than not enough.

TheBear78 · Sep 3, 2023

You can put a larger skimmer on a timer if youre worried that it's pulling too much out.
Its difficult to increase the output of a smaller one...

Lbrdsoxfan · Sep 3, 2023

Curve 9, that curve 7 with the possible bioload aint gonna cut it. Always go with the 'high' bioload numbers when corresponding skimmers with tank size.

shakacuz · Sep 3, 2023

Lbrdsoxfan said:
Always go with the 'high' bioload numbers when corresponding skimmers with tank size.

this! always think longevity. if you oversize certain equipment, you’ll save money on upgrades down the road

Gundy · Sep 3, 2023

Good advice from previous posts. If you have, or are thinking of adding a roller filter, you would probably not need to oversize the skimmer.

Dan_P · Sep 3, 2023

reefinginBD said:
I'm setting up a 150 gallon mixed reef tank and I'm currently debating on whether I should go with the Bubble Magus Curve 9 Elite or the Bubble Magus Curve 7 Elite.
I will have around 25-30 fish with 6-8 of them being on the bigger side. I'll feed the fish with pellets and occasionally feed nori to the tangs. For mechanical filtration, I will have two 4-inch filter socks. The tank will be a mixed reef with a mix of all the different types of corals. Water changes will be done bi-weekly or as needed. I do not want to oversize the skimmer too much but also do not want to undersize it. So, which sized skimmer should I go with? Do let me know! Thanks in advance!

Since water cannot be over skimmed, when you put in a larger than the recommended size, what you are getting is a faster skimming rate. An undersized skimmer might not be able to keep up with dissolved organic carbon waste production, which could result in high DOC concentration.

reefinginBD · Sep 4, 2023

exnisstech said:
I can't recomend which skimmer but I will say in this hobby as many things too much is better than not enough.

Definitely that’s true but I also heard that if I mainly want to keep lps corals and ones that like “dirty” water then over skimming will be a problem. Let me know what your opinion is on this!

reefinginBD · Sep 4, 2023

TheBear78 said:
You can put a larger skimmer on a timer if youre worried that it's pulling too much out.
Its difficult to increase the output of a smaller one...

So like if I keep more lps corals and ones that like “dirtier” water in general then I can just keep my skimmer off for a few hours everyday and I’ll be fine? But would that cause the level of dissolved oxygen in the water to go down? Would using an air pump help combat this problem? And finally, will turning the skimmer on and off every day cause any problems to the pump or anything else in general?

reefinginBD · Sep 4, 2023

Lbrdsoxfan said:
Curve 9, that curve 7 with the possible bioload aint gonna cut it. Always go with the 'high' bioload numbers when corresponding skimmers with tank size.

Yeah I was looking at this in BRS as well but then again in their videos they said to take into account not only the number of fish but also how much I’m going to feed them. Which I’ll do only once or twice a day with pellets. So let me know!

reefinginBD · Sep 4, 2023

shakacuz said:
this! always think longevity. if you oversize certain equipment, you’ll save money on upgrades down the road

Yeah that’s what I always hear. It’s always better to spend once than do it twice.

reefinginBD · Sep 4, 2023

Gundy said:
Good advice from previous posts. If you have, or are thinking of adding a roller filter, you would probably not need to oversize the skimmer.

I was really thinking of going that route but the problem is that often times the filter rolls are not available here and I just want one less moving part. So, I’ll probably just go with the socks. I also saw this video where a guy puts polyester filling inside the socks and changes that out every few days, making the socks last longer, so I may do that as well.

reefinginBD · Sep 4, 2023

Dan_P said:
Since water cannot be over skimmed, when you put in a larger than the recommended size, what you are getting is a faster skimming rate. An undersized skimmer might not be able to keep up with dissolved organic carbon waste production, which could result in high DOC concentration.

I’m afraid that if I get an oversized skimmer, it will be too big and will overskim the water in the sense that it will be great for sps corals in general but not the best for the corals that thrive in “dirty” water. I mostly want lps and corals of that sort which like a little nutrients. I’ll also have a refugium section. So, let me know what I can do. Someone also told me that I can just leave the skimmer off for a certain period of time everyday. But will that cause problems with the skimmer itself or the amount of dissolved oxygen in the water? Then what I can do is run an air pump in the sump when the skimmer is off to help balance that.

Lbrdsoxfan · Sep 4, 2023

reefinginBD said:
Yeah I was looking at this in BRS as well but then again in their videos they said to take into account not only the number of fish but also how much I’m going to feed them. Which I’ll do only once or twice a day with pellets. So let me know!

I stand by what I said, doesn't change anything.

reefinginBD · Sep 4, 2023

Haha thanks. Will just bother you one last time, will overskimming cause problems with lps corals and the ones that like “dirty” water in general? I know it won’t be a problem for sps tho. Is there any solution to that?

Lbrdsoxfan · Sep 4, 2023

reefinginBD said:
Haha thanks. Will just bother you one last time, will overskimming cause problems with lps corals and the ones that like “dirty” water in general? I know it won’t be a problem for sps tho. Is there any solution to that?

Nope. With that projected bioload I wouldnt even think or worry about it.

Again as said above...

If your running a heavily stocked 150g, I'd suggest the curve 9 at a minimum. Personally I'd be looking at bigger as I feed very heavy.

EDIT: added info on the right skimmer!!

reefinginBD · Sep 4, 2023

Lbrdsoxfan said:
Nope. With that projected bioload I wouldnt even think or worry about it.

Again as said above...

If your running a heavily stocked 150g, I'd suggest the curve 9 at a minimum. Personally I'd be looking at bigger as I feed very heavy.

Ah I see, thank you so much!

exnisstech · Sep 4, 2023

reefinginBD said:
Definitely that’s true but I also heard that if I mainly want to keep lps corals and ones that like “dirty” water then over skimming will be a problem. Let me know what your opinion is on this!

You could skim dry so you really don't remove too much. I'm not a die hard skimmer guy. I run them but I skim so dry I'll probably empty my cup every week or two and even then it's not full. I use them for aeration more than nutrient removal. I just tested yesterday and my 180g mixed reef with a skimmer skimming dry had nitrates at 20 and phosphate at 0.65 so it's possible to run a skimmer and still have dirty water.

reefinginBD · Sep 4, 2023

exnisstech said:
You could skim dry so you really don't remove too much. I'm not a die hard skimmer guy. I run them but I skim so dry I'll probably empty my cup every week or two and even then it's not full. I use them for aeration more than nutrient removal. I just tested yesterday and my 180g mixed reef with a skimmer skimming dry had nitrates at 20 and phosphate at 0.65 so it's possible to run a skimmer and still have dirty water.

Ah I see thanks! Yeah definitely you can still use a skimmer and have dirty water, I am just afraid that oversizing it would reduce the nitrates and phosphates too much. So, will keeping it off for a few hours a day and dry skimming help to fix that solution if for some reason the water is "too clean" for lps and softies? I also want to run the skimmer not only for cleaning the water but also for aeration, so will keeping an air pump on while the skimmer is off help to solve that problem of having low dissolved oxygen? Let me know, thanks!

exnisstech · Sep 4, 2023

Personally I would just dial the skimmer back so it doesn't fill the cup or fills it slowly enough you won't have to worry about it removing too much rather than run an air pump. I think it will provide better aeration than a air pump.