Filters and Planted Tanks....

[Lonewolfblue]

Now here's something that I've really been thinking about. How much filtration do you really need in a planted tank? Since the plants do a lot of the filtration for you, do you really need the amount of filtration as on a non-planted tank? That is my topic for discussion here.

Let's say I was planning on setting up 4 55G tanks and heavily plant all of them, kind of like on my 75G. Would I really need a filter like the XP2 or XP3 on it, or would an XP1 filled with the sponges and filter floss do just fine? As for the bio-filter, the plants already have that covered, so all I would need is mechanical filtration, correct? So would I really need as much turn-over as a non-planted?

 

[DarylF2]

Similarly, with full (regular) filtation and a moderately or heavily planted tank, can the aquarium safely hold more fish than normal, with no added health issues?

 

[fish_4_all]

I think it is very doable and the only real issue would be circulation. As long as a current is provided to prevent dead spots then it should be fine. Will I do it, not unless I can figure out how to get a heavily planted tank to grow.
The CO2 mister idea would be awesome for circulation and maybe allow for a smaller filter.

 

[rich311k]

It would make sense to me, that if you have a well planted aquarium, the plants will use the available N and you could get away with a smaller filter simply for mechanical filtration and water movement. The plants would be able to replace the biofiltration usually handled by the filtration system.

 

[Jchillin]

From time to time, I've noticed that the intake is clogged and there is no current (outflow) in my tank. I had no idea of how long these events lasted but there was no negative affect on the fish at all.

I suspect that the filtration we need is only mechanical...removal of waste. Other than that, a heavily stocked tank does the bio-chem filtration on it's own. (yeah, what Rich just said)

 

[Lonewolfblue]

That's why I brought this up, mainly to just remove any free-floating waste, and some circulation. And if dead spots, could add a small powerhead for further circulation. And then if something did go a little sideways, the filter on the tank should maintain the little bio-filtration needed til everything is back in line. Thought I'd bring up the topic, as it's an interesting concept.

Similarly, with full (regular) filtation and a moderately or heavily planted tank, can the aquarium safely hold more fish than normal, with no added health issues?

I believe it could. The heavier planted, the more bioload it can handle. But the question now remains, how much room does the fish need before they feel uncomfortable, too crowded? That would be the only guidelines you would need to follow. Fish such as tetras, the more the merrier, and can have a lot. I currently have 32 fish in a 26G Plated Bowfront, fairly evenly distributed, lower, middle, and upper tank. Far from the 1 inch per gal. rule. And the only reason my nitrates were going off the chart is I was dosing the same as my 29G, which was my mistake. Now I know I need not dose nitrates, dose just a tiny amount of phosphates, and regular doses of Potassium and Excel. Thanks to LaMottes, LOL.

 

[MarkP]

I've had a similiar thought, and come to this tenative idea myself (On bio-filtration for planted tanks)

Yes, the plants will "eat" ammonia/ammonium, and actually prefer it to Nitrite or Nitrate. However...

1. If your ammonia production slightly exceeds the consumption, you could build up ammonia fast. Ammonia is toxic in relatively small amounts, you could end up in the danger zone quickly.

2. How fast do the plants absorb ammonia? Will they suck it up instantly, or will a small concentration be present that will make the fish uncomfortable? I don't know, but think of this- If bacteria weren't faster at "eating" ammonia then your plants, you'd never develope significant amounts of the Nitrafying bacteria at all, and never see a "cycle" in a planted tank.

3. If you ever bottom out on just about anything, your plants won't be able to "eat" ammonia. Don't run low on Phos. or Potassium.

4. I've never DONE it, just thought about it. The risks I mention might be completely wrong. Try it and let us know?

 

[Toirtis]

Your filtration requirement, despite the amount of plants in the tank, will vary based on the overall animal bioload (but unless you have only a very, very few fish in the tank, filtration will still be required), and a filter that has just sponges in it, will be providing both mechanical and biological filtration anyways.

If you are lacking in filtration and water changes, and have a fair number of fish (ie more than 6-8 cardinal tetras in a 55), no matter how many plants you have in the tank, the water will go sour quickly, and waste build-up can cause pH crashes, which your plants will not like at all.

 

[Lonewolfblue]

If you are lacking in filtration and water changes, and have a fair number of fish (ie more than 6-8 cardinal tetras in a 55), no matter how many plants you have in the tank, the water will go sour quickly, and waste build-up can cause pH crashes, which your plants will not like at all.

I'm not sure it would go sour quick, as there's bacteria not only in the filters, but the gravel itself. But my main question wasn't no filtration, but smaller filtration, as in a smaller filter. Yes, it would have some bio-filtration as well, as it has sponges and floss, but would you really need the full-sized filter for the particular tank if it's heavily planted? I'm thinking that you wouldn't. As long as you have circulation and a means of mechanical filtration with some bio-filtration capacity, you wouldn't need the full sized filter for that tank.

Also, as I didn't mention, but I didn't mean less maintenance or water changes. Your schedule would remain the same, 50% PWC's weekly, dosing nutrients if necessary, etc. Just a smaller filter to help cut costs of a complete system if the bigger filter is really not needed. Nothing else would change.

 

[Guest]

This is starting to sound like reef filtration. Just add tons of lr for natural filtration. Sounds like the same idea for the planted tank. I think your on to something ther LWB. That 10 gal planted of mine pretty much ran filterless after the first couple months. I got tired of replacing pads on my hob and finally just left them out. So pretty much the tank just had a hang on back power head, and did just fine. The tank was overgrown with about 20, breeding like rabbits, guppies worth of bioload.

 

[Jchillin]

We actually have several members with planted tanks that have no outside filtration systems on them at all. Hopefully they will stop by and add their experience.

 

[czcz]

I only use biofiltration in a tank with a goldie, fwiw. My other tanks have a good amount of fish and use plants as filters, and I've been stocking kind of heavily over the past months. Plants are good and our friends; we shouldn't underestimate them

As for the bio-filter, the plants already have that covered, so all I would need is mechanical filtration, correct?

You don't need mechanical filtration though. 50%% water changes weekly by itself is great at removing particulates.

From time to time, I've noticed that the intake is clogged and there is no current (outflow) in my tank. I had no idea of how long these events lasted but there was no negative affect on the fish at all.

Yeah, fwiw sometimes I go with no circulation in some tanks just to do it. Tanks are cool in this way, but plant growth and fish movement makes these tanks more like ponds than aquariums to me. It is pleasant but boring.

2. How fast do the plants absorb ammonia? Will they suck it up instantly, or will a small concentration be present that will make the fish uncomfortable? I don't know, but think of this- If bacteria weren't faster at "eating" ammonia then your plants, you'd never develope significant amounts of the Nitrafying bacteria at all, and never see a "cycle" in a planted tank.

The faster the plant grows the faster its uptake, and things like Anacharis and Hornwort uptake very quickly (see Tables from Walstad's study). In applied tanks a mix of slow and fast growers are still so efficient my moderately-high stocked tanks do alright, and my fish seem happy, fwiw.

3. If you ever bottom out on just about anything, your plants won't be able to "eat" ammonia. Don't run low on Phos. or Potassium.

I think there will still be some N uptake with low P and K, but of course low nutrient levels won't be an issue a properly dosed moderate uptake or higher tank.

4. I've never DONE it, just thought about it. The risks I mention might be completely wrong. Try it and let us know?

Your thinking is good. Fwiw all the tanks in my sig use plants as biofilters. It's easy with "Natural," high-tech, or anything in-between.

 

[SCFatz]

Interesting dicussion Wolf.

First a question:How deep below the sustrate can the bacteria live before the enviroment becomes too anerobic for its survival?Is there a general "rule of thumb" for that?

My thinking ,at least at this point in my aquatic journey,is the bacteria is everywhere at can be....and the population is as thinned out as possible regardless of the size of the population.

By that I mean the concentration is the same on/in an inch filter pad or other media as is on the sustrate as it is on a plant ect.

So I'm thinking a planted tank offers an oppertunity for less biofiltration because of the incredible amount of surface area in the water column the plants themselves provide for bacterial live.

 

[Purrbox]

Actually it isn't that new of a concept. If you re-read the filtration sticky at the top of the forum you'll notice that it mentions that a heavily planted tank really only needs mechanical filtration and circulation. Something else to keep in mind is that the bacteria that makes up our biofilter will live on any surface including your plants. Just think of all the surface area a heavily planted tank provides to plants.

I currently have three planted tanks running with no filtration. They all have an water pump that powers the CO2 reactor and provides circulation. This has been working very well for several months now. All three tanks get at least a 50% water change each week. Of course only one of the tanks has any fish in it right now and is only lightly to moderately stocked. The fish have never shown any problems and appear to be very healthy.

 

[czcz]

Good points, Fatz. As I understand, the high uptake of plants will consume at least some of NH3/4 before the bacteria does. In the end there is still bacteria of course. The most appealing aspect is that we don't have to care about and coddle nitrifying bacteria so much with the saftey of plants.

Please correct me.

 

[Lonewolfblue]

Interesting dicussion Wolf.

First a question:How deep below the sustrate can the bacteria live before the enviroment becomes too anerobic for its survival?Is there a general "rule of thumb" for that?

My thinking ,at least at this point in my aquatic journey,is the bacteria is everywhere at can be....and the population is as thinned out as possible regardless of the size of the population.

By that I mean the concentration is the same on/in an inch filter pad or other media as is on the sustrate as it is on a plant ect.

So I'm thinking a planted tank offers an oppertunity for less biofiltration because of the incredible amount of surface area in the water column the plants themselves provide for bacterial live.

Very well said.....

 

[hashbaz]

I seem to be the extreme minority in thinking that we should not "skimp" on the filter for a planted tank.

Under normal, ideal circumstances we could get by with less filtration, but what about when things go sour. The first one that comes to mind is doing a black-out to fight cyano. After a few days with no light, the cyano and some older portions of plants will have died and started to produce ammonia, and the plants are no longer absorbing ammonia.

When I first set up my 75gal planted I ignored the filter. I got a bad algae bloom a few weeks later. Here is what I think happened: The filter inlet got so clogged that the flow rate dropped substantially. This caused a large die off in the bacteria. The ammonia started to rise but was "eaten" by the plants before it got high enough to register on a test kit. Then with the slightly elevated ammonia levels, the bacteria bloom was able to take over. I started

Once again, this is just guess work, but I think that plants cannot keep the ammonia quite as low as bacteria. So relying on plants to "biofilter" your tank may not be the safest route.

On another note, I have a LOT of older leaves die in my tank and need massive amounts of mechanical filtration.

JMO

 

[MarkP]

It appears older and wiser heads have already tried this method. I rather suspected that less biofiltration would be required, but certainly would have been hesitant to try no biofilter! And, to tell the truth, it may have failed on my moderately planted/low light tank anyway.

Of course, I subscribe to the overfilter/understock school of thought anyway- I can't imagine setting up any tank without at least a cheap, wall mart HOB filter. But this may convince me enough to maybe loosen my stocking rules a bit in the 45 gallon (Currently about 30 inches of fish based on current size, but like to leave room for them to grow. Plant growth is enough that I have to dose nitrates.).

No, actually, it probably won't convince me to add more fish- It'll just let me sleep sounder knowing they have plenty of room.

 

[Lonewolfblue]

I seem to be the extreme minority in thinking that we should not "skimp" on the filter for a planted tank.

Under normal, ideal circumstances we could get by with less filtration, but what about when things go sour. The first one that comes to mind is doing a black-out to fight cyano. After a few days with no light, the cyano and some older portions of plants will have died and started to produce ammonia, and the plants are no longer absorbing ammonia.

When I first set up my 75gal planted I ignored the filter. I got a bad algae bloom a few weeks later. Here is what I think happened: The filter inlet got so clogged that the flow rate dropped substantially. This caused a large die off in the bacteria. The ammonia started to rise but was "eaten" by the plants before it got high enough to register on a test kit. Then with the slightly elevated ammonia levels, the bacteria bloom was able to take over. I started

Once again, this is just guess work, but I think that plants cannot keep the ammonia quite as low as bacteria. So relying on plants to "biofilter" your tank may not be the safest route.

On another note, I have a LOT of older leaves die in my tank and need massive amounts of mechanical filtration.

JMO

This could be a good point, but as stated above, we are not talking about removing filtration, just smaller. As stated above, anexample of instead of running an XP3 on a tank that would normally require an XP3, fully plant the tank and only run an XP1. Costs less and money saved. And where could that money saved go? More plants of course. Also, as stated above, the filter is not the only thing that holds bacteria. So even if things try to go sour, if a well maintained system, there should be ample supply of bacteria to take care of the job, on the plants, rocks, ornaments, gravel, etc. It's not the point of removing filtration, but having smaller filtration. Personally, if you are properly maintaining a tank, and have your dosing and maintenance down pat, you shouldn't see any algae blooms that would need blackout. Now I can see having proper filtration in the beginning, but on a mature tank, you should be able to remove it and put something smaller on, and transfer the media from the larger filter to the smaller filter, without any damage to the system as a whole. Now with one of the new 10G tanks I'm planning on getting, I just might try filterless, starting with just plants. Then when they fill in and get established, add some fry that I may have at the time and allow them to grow.

 

[azn_fishy55]

IME I had a 30 gallon heavily planted/heavily stocked(maybe about 3"-4" fish/per gallon) with a Whisper HOB filter rated for 10-15 gallons and an Aqua Clear filter rated for 10-20 gallons,I had DIY CO2/Excel and I had no issues at all with the tank(after getting rid of the green water).Though what might have not made the tank go sour is that I did EI and removing 50% water once a week and the water stayed crystal clear(after green water).