How to size a pump to your tank

**CHOMPERS** · 09-08-2009, 12:08 AM

Originally Posted by garhog;3420228;

ok so following pump sizing so far but wondering if a larger tanks and ponds need the same amount of turnover assuming they have the same bio load

There are different definitions for 'pond'. For a pond that is a dirt hole filled with water, the care is different entirely. Aeration or circulation is only needed to prevent stratification (thermocline and/or layering). Mother nature takes care of the rest. For a concrete or vinyl creation that resembles a dirt hole, the care is also different and unique. Mother nature is removed from the system for the most part, so filters are added and circulation should be increased. For plastic tubs with volume to surface area ratios resembling aquariums, you would want to take care of them as if they were an aquarium.

**Scubarod** · 01-03-2010, 10:01 PM

Yes very interesting. I found some info for you Little giant fans.

check it out
http://www.lgpc.com/ProductFiles/SpecSheets/995038.pdf

Make sure you scroll down to the tank set ups

**md1017** · 02-01-2010, 2:21 AM

Oh well...i should've found this website 5 months earlier. It turns out that my filter is underpower for my tank. I have fluval 305 (1000L/hour or 240 gallon/hour). My tank is 40"x18x18 which gives me 54 gallon. And if it has to be 5 times that, then I should get a filter with around 270 gallon / hour =( Is my calculation right? No wonder I never get ammonia level below 0.05...no matter what I do. I have 2 10" oscar and 5 5" silver dollar. The 305 is fully loaded with seachem matrix and biomax, no carbon etc.

**Pharaoh** · 02-01-2010, 6:52 AM

Originally Posted by md1017;3845114;

Oh well...i should've found this website 5 months earlier. It turns out that my filter is underpower for my tank. I have fluval 305 (1000L/hour or 240 gallon/hour). My tank is 40"x18x18 which gives me 54 gallon. And if it has to be 5 times that, then I should get a filter with around 270 gallon / hour =( Is my calculation right? No wonder I never get ammonia level below 0.05...no matter what I do. I have 2 10" oscar and 5 5" silver dollar. The 305 is fully loaded with seachem matrix and biomax, no carbon etc.

Your turnover rate most likely will not affect your ammonia reading in this case. You have a very high bio-load for that tank. The ammonia that you are seeing is output from the fish. You most likely do not have enough area for the bacteria to colonize in order to take care of the nitrates.

What is your water change interval and amount?

**md1017** · 02-01-2010, 8:20 PM

Originally Posted by Pharaoh;3845327;

Your turnover rate most likely will not affect your ammonia reading in this case. You have a very high bio-load for that tank. The ammonia that you are seeing is output from the fish. You most likely do not have enough area for the bacteria to colonize in order to take care of the nitrates.

What is your water change interval and amount?

I do water change every week for about 20%.

I have installed a helper filter and I placed it at the other end of my tank opposite fluval 305 water inlet. (internal cannister running at 800L/hour stuffed with matrix) Seachem ammonia allert keeps on green (alert). I add stability for a cup full for every 3 days. I change water with seachem prime.

Hmmm bio load...I dunno the tank still looks big enough for them...but maybe I am wrong as I am a newb in this hobby.

So do you think I should put my fish in 100 liter (separately, I have few 100 liter or 20 gallon) plastic container until my tank stabilize?

**Pharaoh** · 02-02-2010, 7:06 AM

Originally Posted by md1017;3847407;

I do water change every week for about 20%.

I have installed a helper filter and I placed it at the other end of my tank opposite fluval 305 water inlet. (internal cannister running at 800L/hour stuffed with matrix) Seachem ammonia allert keeps on green (alert). I add stability for a cup full for every 3 days. I change water with seachem prime.

Hmmm bio load...I dunno the tank still looks big enough for them...but maybe I am wrong as I am a newb in this hobby.

So do you think I should put my fish in 100 liter (separately, I have few 100 liter or 20 gallon) plastic container until my tank stabilize?

I would advise you to get a water test kit and do two thing. Test your tap water and test you tank parameters. To keep the parameters in check with such a large bioload, you might have to do bigger water changes.

Also, bioload does not necessarily always refer to the size of the fish. Some fish are just dirtier that others. Oscars are know for messing up a tank rather quickly, especially something as small as a 54 gallon.

**md1017** · 02-08-2010, 8:10 PM

Originally Posted by Pharaoh;3848736;

I would advise you to get a water test kit and do two thing. Test your tap water and test you tank parameters. To keep the parameters in check with such a large bioload, you might have to do bigger water changes.

Also, bioload does not necessarily always refer to the size of the fish. Some fish are just dirtier that others. Oscars are know for messing up a tank rather quickly, especially something as small as a 54 gallon.

Hi Pharoh, thanks for your help. It turned out that my filter was actually underpowered. I replaced the 305 with fx5 =D. And it works like a charm. And I stuffed the fx5 with biomedia (some biomax, some matrix, some bioballs and few layers of scrourer pads at the bottom chamber for water polisher) I did add stability because I am adding more bio media for the new filter.

And about the tank size, there is something confusing me because my actual tank spec is 120cmx54cmx54cm or 4feetx18inchesx18 inches and it equals to 350 liter or 87 US gallon (1 us gallon is 4 liter)
But when I used the formula provided on the beginning of this thread. It shows that my tank is only 54 gallon??? I might ahve done something wrong lol. I am so stupid in maths

My seachem ammonia alert is now showing yellow. (safe) I got water test kit and ammonia test shows yellow, but nitrite is still bit high (purple) or about 0.1. Currently treating it with fluval nitrite remover. Hope it will clear in a week or even before that. One thing I am confused tho, why it has nitrite when ammonia level is almost non existent??

I did test my tap water and it's crystal clean.

Also I changed the feeding habit. I used to feed my fish 3 times a day. NOw I only feed them once or twice a day for about 3 minutes each.

Now I have 5 silver dollars (about 12-13 cm in length), 2 big oscars and 1 pleco perdalis (30 cm) and until today, my tank is crystal clear.

**nolapete** · 02-18-2010, 1:20 PM

Don't understand why you'd go through L/12 x W/12 x H/12 * 7.5 when you can just do L x W x H / 231 (cubic inches in a gallon). :P

Nevermind, I get it.