Turnover rate question

[affableamerican]

I know this is a total newb question, but what is the recommended tank turnover rate for a reef? I keep reading about 5x and 6x the main tank water volume, but I thought it was supposed to be much higher. In my only previous tank, I had a 20g with 10g sump and about 350-400gph turnover (which is around 15-20x)! And it didn't seem like too much flow at all. With my new 45g, I can't imagine only turning over 250gph (i.e., 5x) -- I was thinking I would get a mag9.5 and have a 15-20x turnover rate. Can someone please clear this up for me? Thanks!

[theatrus]

Though the sump, 5-6x is good.

Through the main tank, 10-20 is good.

[hodsgod]

I believe 10 is for FOWLR and 20 is for a full reef tank, as a guideline of course.

[PatMayo]

Some folks that do bare bottom tanks and have sps have as much as 40 to even 80 times tank turnover. The slower volume is for the sump. My tank is a 90 with a mag 7 pump. This is about 4 x. The tank has about 30 times turnover.

Because I have a mixed reef and a sandbottom much more flow than that and my sand would be flying everywhere. In fact it did when the tank was brand new. Once the sand got some bacteria and age on it the flying around stopped.

Regards,

Pat

[affableamerican]

Hmm... so on my 45g, why an overflow rated for 800gph if the recommended sump flow-through rate is only ~6x (~225gph)? And what are the drawbacks of a high sump flow through rate? And if I have a fuge in the sump?

Thanks!

[Yinger]

i think it honestly varies from tank to tank. I have about 65x turnover on my tank right now, but I've seen tanks with 17x turnover with awesome coloration and growth. you mainly just want to get a nice flow around all your corals and you'll be fine. and some SPS keepers actually go above 100x turnover. And with the sump/return, my turnover is like 4-5x.

[SeanySean]

<a href=showthread.php?s=&postid=7986646#post7986646 target=_blank>Originally posted</a> by affableamerican
Hmm... so on my 45g, why an overflow rated for 800gph if the recommended sump flow-through rate is only ~6x (~225gph)? And what are the drawbacks of a high sump flow through rate? And if I have a fuge in the sump?

Thanks!

I have a flow rate of around 10x....

Drawbacks of having a high flow rate through the sump.....

Noise issues
Microbubble issues
You will need a bigger sump

i am sure there are more, but those are the problems I have had to deal with

I think what your saying on the overflow rated at 800G/ph, is that is the max it can handle, but does not mean you have to achieve that

Sean

[ericwebster]

I have a mag 18 with 2 3/4 return lines -- I do have a microbubble problem but I think its due to my skimmer. Should I add more baffles to capture them or put a ball valve on my return pump to restrict it?

[ericwebster]

There is lots of good strong flow in the tank .. and the sand bed has seemed to settled down

[MJAnderson]

You have a Mag 18 on a 72g tank? That's 1800gph. Do you run powerheads as well? I swapped out a Mag 7 for an Eheim 1250 on my 72g for a return pump. Silent, no bubbles, no heat. Just added 2 modded MJ900s in the main tank

[ericwebster]

I have one MJ1200 in the tank .. moving water in a spot where there isin't alot of flow from the return lines.

There are some "quiet" areas in the tank in case a fish wants to relax .. I thought there was no such thing as too much flow? I figured an actual reef has a lot more flow than what any pump could create.

Thoughts?

[MJAnderson]

Well this is a personal thing, but getting all your flow from your return pump has some issues, mostly with efficiency.

The Mag 12 generates 1200gph but you probably only get 1000gph with head pressure and plumbing. Running this pump will cost you about $12 a month in electricity and adds heat since it's a 110w pump, sitting submerged. Plus the microbubbles in the sump. The MJ uses 20w and has about 300 flow for a total of 1300gph in the tank and 130w of heat/electricity

Switch to a single Tunze 6060 and a low flow pump (eheim 1250 for example). Total electric usage will drop to 39w, saving you about $10 a month. So in the first year you've saved enough to buy the pump and 1/2 the powerhead. In the second year it's all profit. You've increased your gph in the tank to 1800gph, reduced some locline (im guessing) you used to redirect all that return pump flow and swapped one powerhead for another (although larger).

Better yet, wait until the nanostreams come out in September. The 6025s use 7w and push 660gph for $60. Two of them will give you equal flow and much more coverage. 6045s are about 1100gph for $100

http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=Tunze_pumps

[Amphiprion]

My tank has a 3" sand bed and I still have nearly 85x hour turnover (of course, the vast majority of this is in the tank). It is a mixed tank with reasonably heavy growth, so this much flow is necessary for me. Newer tanks can start off with less and will need more as the tank progresses.

[ericwebster]

Well i had a mag 12 which died on me .. I needed to get the water moving and I splurged for the 18 figureing I could split it.

My overflow is doing fine .. everything is moving well .. who knows I may want to upgrade in the future. I have 3 PC's which run 110 in the house. I could shut one of them off .. ;)

Anyways -- I can't bring back the pump now.

[SeanySean]

to check if it is your skimmer, just turn it off and see if your micro bubbles go away, if they do not you will have to add more baffles, or use another method such as sponge (this is what I use sponge for)

Sean