Biofiltration and gph

[Plum]

Does it matter how many gallons flow through the bio filter?

For example, if I were pumping 1000 gph through the bio filter, and increased this to 2000gph, is there a benefit? Disadvantage? No change?

Thanks,




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[duanes]

The amount of dissolved oxygen is more important than gph, as nitrobactor and nitrosomonas use oxidation to convert ammonia and nitrite. However a more powerful flow usually ends up with more DO as it flows and cascades thru pipes and over media.

 

[David R]

It is all about balance; not enough GPH over a large amount of media and you won't turn over your tank often enough to keep the water clean, too much gph over too little media will not give the water enough exposure to the bacteria on the media. There would be little advantage of a 100% increase in flow if you don't have a large enough volume of media to give sufficient exposure, but if you've got a lot of media and 1000gph is only a fraction of what it is capable of handling then and increase in flow will certainly be worth while.

So yes, the GPH flowing thru the bio media is important but it isn't the sole factor. Hooking a Reeflo dart up to an eheim 2223 canister so it flows a million GPH won't make it filter a 600g tank...

 

[Drstrangelove]

Does it matter how many gallons flow through the bio filter?

For example, if I were pumping 1000 gph through the bio filter, and increased this to 2000gph, is there a benefit? Disadvantage? No change?

Thanks,




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If the bio filtration is adequate to the task it can accomplish this at a very slow rate. Going faster has the advantage of moving toxic chemicals away from the fish quicker, but as at higher gph, each pass has a shorter contact time, it forces you to have to recycle the same water repeatedly if the bio material can't remove the toxins the first pass. Lower contact time means higher turnover rate (higher gph), which is more expensive from an energy standpoint.

So, yes, if by going slower you could increase contact time and accomplish the same bio process and you go faster instead, it does cost more. However, the total contact time in the filter does not change (although each pass is quicker), so the filter accomplishes the same result ultimately.

If you have a large bio load spike (e.g., feeding a tank of large, messy carnivores every 3 days), and a slow gph (especially if the water has minimal water movement within the tank), there is a legitimate concern with taking too long to make the first pass.

So, as others have said, there is no 'correct' answer or rate. Each tank is different and even a particular tank may change as the pets get larger or the filters get clogged.

Faster gph has a different strategy for mechanical depending on what type of mechanical filtration you have, but again, each tank may be optimal at different rates and that may change as the filters become more / less efficient.

 

[Plum]

Thanks gents - responses were perfect.

Will have to adjust and measure -

Thanks again.


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[lp85253]

if you really think you dont have enough bio-filtration ...it will more likely pay more dividends to increase your bio media ..slightly...gph really does more for mech. filtration ..

 

[Plum]

I think my bio is satisfactory, I am adjusting my pumps though, so getting more information.

Total of 1800 gallons - ultima II 4000, 150 is a sump, with minimal bio.

Stocking is quite light - about 20 piranhas or so.

Pump is a reeflo hammerhead, though thinking of either adding multiple laguna 4200's, or replacing the hammerhead with the lagunas.

If I replace the hammerhead pump which drives the ultima II - flow will be reduced in bio filter.....




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[aldiaz33]

I think you will be perfectly fine running less GPH. By MFK standards, I have a lightly stocked tank, but I only turn my tank over ~2 times per hour and my water is always on point.

Public aquariums run less than 1 turnover per hour on their huge displays. I actually read that slower flow is beneficial in that there is more contact time with your bio media.

I did a quick search, but didn't find any pix of your setups...I would love to see them; can you post a few up?

 

[jlnguyen74]

I think my bio is satisfactory, I am adjusting my pumps though, so getting more information.

Total of 1800 gallons - ultima II 4000, 150 is a sump, with minimal bio.

Stocking is quite light - about 20 piranhas or so.

Pump is a reeflo hammerhead, though thinking of either adding multiple laguna 4200's, or replacing the hammerhead with the lagunas.

If I replace the hammerhead pump which drives the ultima II - flow will be reduced in bio filter...

Do you pump water from your sump thru Ultima 4000 before returning to tank? If you do, then just stick with Reeflo Hammerhead. Replacing Reeflo with Laguna may do more damage than help.

If your drain can handle more flow, you can add a Laguna and return the water straight from the sump to tank, and leave the Reeflo to return the water thru the Ultima.

If your drain can't handle more flow, but you want more current in your tank, just add some strong powerhead.

 

[jlnguyen74]

It is all about balance; not enough GPH over a large amount of media and you won't turn over your tank often enough to keep the water clean, too much gph over too little media will not give the water enough exposure to the bacteria on the media. There would be little advantage of a 100% increase in flow if you don't have a large enough volume of media to give sufficient exposure, but if you've got a lot of media and 1000gph is only a fraction of what it is capable of handling then and increase in flow will certainly be worth while.

So yes, the GPH flowing thru the bio media is important but it isn't the sole factor. Hooking a Reeflo dart up to an eheim 2223 canister so it flows a million GPH won't make it filter a 600g tank...

This is correct! It's all depending on how much media and what type of media do you use? It's also depend on what kind of fish do you keep? Some fish like more current than other.