HOB at night, canister during the day?

[takadi]

I am planning a system where I will be running a canister filter during the day time and an HOB filter during the night. The canister will be providing flow during the day with minimal surface agitation to prevent CO2 gas off, while the HOB will provide the much needed surface agitation at night to gas off excess CO2 and aerate the water, while at the same time giving the fish a break from the strong flow of the canister. The only real problem I can think of is the nitrifying bacteria population eventually crashing due to the inactivity of either filters for those hours they switch off. Comments?

[mickmac247]

Great question and nice to know info also. Maybe someone who has lost power and then their filters restarted might know. Do they just restart them or do they have to start them from scratch...

[GeToChKn]

I think the bacteria won't like it.

[takadi]

Fortunately the HOB's I have (marineland emperors) do not need priming as long as the water level is high enough. I am only concerned with the bacteria dying. I've read that it takes 24 hours for the bacteria to die. I am really hoping for this to work because it seems like a win win situation for me. I have moonlights, so the HOB also creates a beautiful shimmering effect at night.

[diwu13]

As long as the bacteria are allowed to dry out there shouldn't be a problem.

But why not make it easy on yourself and just run the canister 24/7... and have a bubbler on a timer for night time.

[willknowitall]

it will suffocate your bacteria in filters and have a cloudy mess
have you ever had the power go out for 12 hours and seen what it does to a filter and tank, and thats just once in a blue moon that happens, not every day

[aweeby]

other than the bacteria issue, that's a lot of stuff hanging off your tank. Two sets of intake/output can look overwhelming, especially if one of them is attached to a bulky HOB. If you're concerned about current, you might think about adding a prefilter or packing more media to staunch the flow a bit. It'd be more practical to have an intermediate flow 24/7 instead of two extremes during day and night

[msawdey]

I see why you would want this, but your going to be able to obtain what you want though a air pump and for the shimmering water, by adjusting your canister output to brush the top of the water. Its going to be cheaper and your not going to have the issues of the filters not restarting

[takadi]

Thanks for the tips everyone. I think this was just more of an experimental thing I was thinking of. The tank I have has mostly livestock that prefer cold waters or fast moving waters, so I was thinking of re-creating the river environment, with a cycle of currents. If only there were a way to automatically adjust the flow of the canister filter...

[prototyp3]

I don't understand why people seem to regard CO2 as some precious resource we should be conserving at all costs. With good surface agitation you lose a minimal amount of CO2 for the benefit of increased oxygen content. That's a win, not something that should be fought against.

[mordalphus]

Originally Posted by takadi

Thanks for the tips everyone. I think this was just more of an experimental thing I was thinking of. The tank I have has mostly livestock that prefer cold waters or fast moving waters, so I was thinking of re-creating the river environment, with a cycle of currents. If only there were a way to automatically adjust the flow of the canister filter...

I have a small powerhead hooked to my light timer, so the flow increases during the day and decreases at night.

Also, you don't need to offgas CO2 at night, I never have and my fish and plants are fine

[Aquaticfan]

Originally Posted by prototyp3

I don't understand why people seem to regard CO2 as some precious resource we should be conserving at all costs. With good surface agitation you lose a minimal amount of CO2 for the benefit of increased oxygen content. That's a win, not something that should be fought against.

Bingo right here.

The Co2 being off gassed is minimal. Let alone O2 is JUST as important to your tank as Co2 and not just for the fish or bacteria But for plants as well..

As ive stated before how do people Like Tom Barr and others create such great tanks that look so awesome with plants and fish but use Wet Dry filters or sumps that off gas more Co2 then a simple surface ripple or Air pump will do.

[fusiongt]

I think you're just trying to do more work than needed. A canister filter with spray bar will give you plenty of surface agitation and the co2 gas loss won't really matter - your plants will do fine with it. But an alternative would be to simply adjust the spray bar so it creates lots of surface agitation at night, then angle it downwards so there's less agitation during the day.

You'll get tired of doing this after a while, but while you're in your honey moon phase with your tank I think this is a good solution.

[ucantimagine]

If you get something like the eheim shut-off valves, you can just reduce the flow at night.

[ucantimagine]

If you get something like the eheim shut-off valves, you can just reduce and increase the flow whenever you need very easily.