Gph

[IamJoshieG]

Hi, Ive had a 55 gallon freshwater tank for three years now and I am planning on converting it into a reef tank. I was planning on purchasing and using a cannister filter, but Ive noticed that many people suggest having a water turnover rate of at least 10X the size of the aquarium in gallons. That would mean I need a filter with a turnover rate of 550 gallons per hour? That seems very high, and it seems like a pump that powerful would blast water through my tank washing my fish all over the place. Is that really the required flow rate for a reef tank?

[wozza]

i have nearly 2000gph in my 55 i think 550 would be fine, if not a bit on the low side.

[CSeaSee]

First off, WELCOME TO REEFLAND!!
As a broader answer about starting a saltwater tank, I would strongly urge you to do a little more research about filtration, protein skimming, and live rock before starting up a tank. Also, if you are planning on re-using any equipment from your freshwater tank, look up copper poisoning as well- copper will, to be blunt, destroy any attempt at keeping a reef.
And yes, many reef tanks have crazy flow rates- and the fish love it!

[IamJoshieG]

Yes I do plan on researching more and I consider posting on this forum part of my research. Why exactly is the 10X flow rate rule necessary? Is that much flow needed to keep the biological filtration up to par for a reef tank? I was led to believe that live sand and live rock contribute majorly towards the bio-filtration of a reef tank. If 10X was necessary I will certainly buy a filter that is powerful enough to generate that much flow, but I was hoping to be able to purchase an adequate filter for less than 125$ or so. Thanks for the help, I greatly appreciate it.

[wozza]

good one carl , forgot to mention the copper thing.
If you are using say about 1lb of live rock per gallon of tank water then you have no need for extra external canaster filters all you biological filtration will happen in and on your live rock IF you have at least 10x tank vol per hour. to achive this turnover al you need is some powerheads in the tank say 3-4 maxijet 900's.

In my 55 i have 2300lph from my return pump and 4 x maxijet 900's and i still think there is some room for a bit more.

This is a section from one of leebca's sticky posts.
Circulation
Not as important in a FOWLR aquarium as in a reef aquarium, but if you are using live rock, then you want to make sure there is enough circulation to get the nitrogen wastes to the rock. Usually that means no less than 8 to 10 turnovers of the system water every hour. To determine/calculate the turnovers, add the gph of the internal powerheads (Tunze, etc.) to the gph flow of the system pump. To determine the gph of the system pump, you need to know the rated flow of the pump and then the flow of the pump with the head pressure (the resistance to the flow) put on that pump. Get a total gph and divide that by the volume of water in gallons in the system. If that number is no less than 8, you're okay. If that number is below 8 you then want to add another powerhead inside the aquarium or step up to the correctly sized system pump.

hope this helps, james

[CSeaSee]

Here's why you need a high flow rate in your reef tank:
Corals are animals, but they can't move (at least, move appreciably fast). Like anything that's alive, corals produce waste. The way corals get rid of waste is by excreting it into the water around them. This is also how they get (some) of their food, oxygen, etc- directly through the water which is directly next to them.
Corals need high flow to keep their wastes from literally suffocating and poisoning them, and to continually bring in new, clean water. The flow rate of specific corals varies greatly- 10x is usually a starting point for soft corals and Large-polyp Stony (LPS). People w/ Small-polyp Stony (SPS) tanks often have flow rates up to 50x.

In a saltwater tank, your filter is not the chief source of your "flow." People buy powerheads or pumps to circulate the water horizontally around the tank- the simplest set-ups can be likened to a NASCAR racetrack- the water goes around and around at high speeds. More complex set-ups have rotating pumps/powerheads to create random flow.

Also, most people's chief "filter" is a protein skimmer- which is nothing like anything you've used in your freshwater tank. Your filters from a freshwater tank are often secondary, or an afterthought.
You are correct, your live rock and live sand is your biological filter- what a protein skimmer does is remove dissolved waste. You can't see this waste, because it is dissolved, until the protein skimmer pulls it out of the water column. Don't skimp on the purchase of a skimmer- it is the most important piece of equipment you will ever buy for a reef tank.

[Poseidon]

You have received very good advice so far, skip the canister filter and get a good skimmer instead. You can use the MaxiJets for flow, and you will be well on your way to a nice tank!

[IamJoshieG]

ooooh alright, I understand now. I didnt realize that the flow was to help move water towards and away from corals, I thought the flow was for getting a lot of water to pass through the filter. That makes a lot more sense now. One more question i have is about this copper poisening that you guys are mentioning. Do I have to worry about it if ive never used any sort of medications for my tank when it was set up? I only used was liquid and tablet fertillizers a few times.

[wozza]

i think then you will be fine was the tank new when you got it?

[CSeaSee]

i think then you will be fine was the tank new when you got it?

To expand on this, was everything new when you bought it for your freshwater tank?

[IamJoshieG]

yea everything was brand new when I got it.

[wozza]

your all good then ide say!

[CSeaSee]

I agree.

[IamJoshieG]

Awesome, Im glad to hear it! Thanks a lot for your help. Im excited to get this tank started!

[wozza]

feel free to ask any questions you want!

[IamJoshieG]

I just thought of one last question; What about mechanical filtration? If I use a protein skimmer and all together skip the cannister filter, can I just use my old bio-wheel filter to take care of any loose particles in the water?

[CSeaSee]

Yes- just be sure to keep the filter clean, so you don't get a nitrate factory going. There are some who don't use mechanical filtration at all, as well.

[Reefland]

Instead of using any type of mechanical filter, I like to place some filter floss in a high flow area of the tank to help polish the water and remove debris.