External Filter

[modyas]

Has anyone used those external hanging filters( not canister filters). those that hang on the outside of the tank with its own bio/mechanical/chemical filtration layers. Is this good for planted tanks? it seems to be some what like a canister filter only much smaller. Any comments?

[ttl100]

I am using one but mine is DIY home made version with PVC pipes. I don't see any difference in performance compared to the ones you mentioned. So far the filters are doing an extremely good job. If you want the schematics just give me your email add and I will forward you a drawing of my DIY filter set-up.

[modyas]

sounds great will PM u my email add
so ur DIY set is hidden or outside? is it big, cos my dad also did his own but very big haha.

[pipsqueak]

If it's something like the Liberty external/hanging filters, then no, it's no very good for planted tanks. Causes loss of co2. I changed mine to a internal filter upon reccomendation when I started out initially.

[modyas]

is it because when the water flows out down from the top it causes water agitation which causes the CO2 to escape from the water faster? is that the main reason? cos i think beside that it is a very cheap alternative to a canister filter

[axel_wong]

Only internal or external canister filter should be used because filters whose discharge causes heavy turbulence at the surface of the water will enrich the water with O2 and cause CO2 to escape [1].

Reference:
1. I. Scheurmann, "Aquarium Plants Manual", Barron's

[nivlekx]

OIC.... no wonder my tank has so little CO2 even though I am injecting it at like 15 bps...

[naturetan]

One of the ways I suggested to a friend whom unknowingly bought overhead filter is to connect the outlet point to a hose directly into a CO2 reactor. This minimize any agitation on water surface and it works well.

The disadvantage of overhead filter is it take up space, block lights and cause dark shadow for certain location of plants.

[modyas]

So nivlekx, guess i better get a canister man no choice. the pee pee Dymax cannot make it already. Unless i can direct the out flow thru a tubing but i dun think its possible. So see how it goes la

Thanks for your inputs everyone.

[sherchoo]

My question, how big is your tank? If it not too big, an internal filter work quite well.

I've seen some tank s that are using hang-on filters and still do well. Problem is the co2 loss due to water agitation which can be lessen by extending the outlet. By reducing agitation you're reducing gas exchange to the environment avoiding co2 loss. If you already have the hang on filter, try to reduce the surface agitation. Monitor the pH/kH to check the co2 level. It might be enough for a sucessful tank.

What I'm trying to say is that it's not a must to have canister filter. In fact for planted tanks, you do not even need a filter if the bioload is not high.

[modyas]

Thanks for the advice Sherchoo
well i dun have a tank yet haha waiting til exams are over before gsetting up one. was thinking of a 3 ft so options are pretty open and i guess budget will play an important role to the outcome. But i agree with a hanging filter being possible as long as i can modify the outlet of the filter not to agitate the water, so there is a possibility there and defintely more cost effective. as for the bioload, knowing me i will probably keep getting fish haha so i would need a filter Thanks again