How many gallons per hour do you recommend?

[Aquaticfan]

I agree with exactly what people like Diana and HD and others. I to also shoot for 10x. I don't think there is such a thing as to much filtration. Just to much current/pressure inside a tank. There are ways to change that and keep a higher flow/turnover rate at reduced pressure by changing inlet and outlet sizes to larger diameter or dividing flow from one outlet to multiple. Adding multiple also allows you to distribute better flow throughout the tank easier with less equipment in the tank.

[Aquaticfan]

Originally Posted by Steve001

Remember this. Any additional filtration other than merely mechanical removal of solid matter takes away nutrients that would be used by plants in favor of bacteria.

????

Sorry, but how does more filtration take away the nutrients the plants use? Nitrates are not consumed by aerobic bacteria. Only the ammonia and nitrites are. Phosphate or potassium are not consumed at all by bacteria and neither is micro nutrients. Even at that if dosing ferts and nutrients your easily covering what's needed. Especially dosing EI.

If this is possible I'd like to know how as disagree.

[vincenz]

I also shoot for 10x turnover, but that's with powerheads included.

[Complexity]

My 75g and 90g each have two Rena XP4s on them. That comes to 10x for the 90g and 12x for the 75g. I'm very happy with the filtration on both tanks.

One of my 29g tanks has two XP2s while the other has one XP2 and one XP1. That brings those tanks to 21x and 19x, respectively. The filtration is excellent on both tanks, but I do have to throttle back the current on them or it can be too much.

I'd much rather have too much than too little since I can always throttle it back when it's too much.

The other consideration is when you start adding more equipment, such as reactors and uv sterilizers and maybe even inline heaters. Each of these things can reduce the flow and negatively affect the current inside the tank. If the current isn't strong enough, then detritus may settle to the bottom instead of remaining suspended in the water column where it can be sucked in by the intakes. If your flow and current are only sufficient, then they may become insufficient once you try to upgrade your system with additional equipment.

Also, it's much easier to get lots of current flowing through a tank with small plants, but when those plants grow, they can easily block the flow of water. Depending on your design style, this can become a problem. If you're into iwagumi design, then there's no problem. But if you're a plant pack rat like me, then you need a lot of current pushing the water around once the plants grow in if you want it to move through a thicket of plants.

I think personal preference also plays a big role in deciding how much filtration to put on a tank. I prefer having two canisters on each of my tanks which is one reason why my 29g tanks have so much filtration. I also enjoy watching my plants sway in the water current, but not everyone likes that. I also prefer to not fiddle with my equipment any more than I have to so having lots of filtration means I don't have to service my filters as often. By having two canisters do the job, they split the work, so they get only half the dirt, and therefore can go twice as long before needing to be serviced. Given the number of tanks I have, I really like prolonging the amount of time before needing to service my filters.

While the 10x rule is a good starting place, it's by no means a hard and fast rule that everyone has to follow. Different tanks have different needs and different people have different preferences. The best you can do is gather as much information as you can about the prod and cons of different setups and then pick what you think fits your needs and preferences the best. If you change your mind later, you can always sell the old equipment and buy something else.

[talontsiawd]

I am now big on flow. I have had great tanks with only about 3x turnover (advertised, never tested or even looked around online). One of my favorite tanks was a 10 gallon with a Zoo Med 501 and I rarely did water changes. Another was a 29 with the stock filter. I even had pretty decent results on a tank with no filter.

What I have found is you can have low flow and have it work. But, I have also found when I have had issues, changing the filter out for something larger had a much bigger impact than messing with anything else (outside of having too much lighting which is obvious). I have had tanks that just had random issues and I would tweak the light, CO2, ferts, and nothing would change much, especially long term. Putting a bigger filter on helped tremendously.

All my tanks approaching or over 10x turn over are so much easier to deal with in various ways. Stocking is the obvious, but you have more consistency across the board. Most algae doesn't like flow as well so I don't need to start with a crazy amount of plants to avoid algae.



I would say to try to get in the 5x-10x range. It may seem excessive but it makes my life easier. Going lower won't be terrible, again, I have had good luck. I seem to have more luck using a bigger filter though, not that my tanks are automatically better with more flow or do better, they just tend to have less issues.

[Chlorophile]

My tanks range from 2x an hour to 20x an hour..
My 20x an hour tanks have better growth but my livestock act the same as in a 2x tank because I have chosen the right fish for the right tank and stocked appropriately for my filtration level.

Flow rate needed depends on the aquascape, the method of filtration, what species of fish you have and how many fish you have.

But yea in general I think the 10x rule is good to shoot for, If I can help it I avoid under 5x but as I said 2x works fine if you dont mind poop on the substrate.

[Calmia22]

Thank you for the suggestions everyone. I think I will stick to the 10x rule, and good to know so many people follow that as well.