Intricacies of a heavily planted tank

[fishplants]

Hi All,

I placed this post in a previous thread, but haven't managed to elicit any responses - happy to hear from anybody. I am very interested in this and I think others might be as well. You should be able to get the gist of it from the below, if not I can explain the background.

Phoenix44 and Cricketman, would you mind elaborating? (and sorry bottlerocket for hijacking your thread).

If I have read correctly, leaving fish poo/plant pieces etc in the gravel is a good thing as it is a natural fertiliser and the denitrifying bacteria break this down into nitrate, when you are talking about a heavily planted tank.

The bit I would like you guys to help me understand is - if it is good to have this detritus in the gravel, why would you want massive fitration which means more of it gets trapped in the filter and less in the gravel? While obviously the results of the breakdown of the detritus (NO3) is still available via the filter, why bother with massive filtration if the gravel is sufficiently performing the task? It sounds like you guys are not really using the filter mainly for it's biological capabilities?

Is the filter there (almost) purely as a water polisher ie cosmetic value?

I suppose that where I am going with this is, that if you have 'trained' the bacteria living in your gravel to deal with massive amounts of waste (more so than if you vacuumed weekly/fortnightly/monthly, then a biological filter is less of a requirement rather than more. Make sense?

In my (rather simple) mind, your gravel will be doing such a great job that you could run one filter with filter wool only (no biological media at all) just to ensure suspended matter is removed from view?

Also, if NO3 for the plants is so desirable, why have such large/frequent water changes?

Your thoughts would be most welcome.

cheers

Something else I just thought of - if you are adding fertilisers to a planted tank why would you have Phoszorb and Nitrazorb in your filters? Essentially you are putting the fertiliser in to have the good bits removed. Also, the nitrates that are being created by the intentional leaving of fish waste, for the purpose of plant health, will also be removed by the Nitrazorb. I am a smidgen confused!

Always willing to learn.

cheers

[mac]

Okay I wont as such answer our question a round about way.

But this is how I do what you are saying. Now get this I never ever vacuum my gravel. Just leave it the way it is.

So an example is this. I have a 48in 20in 20in [And I know we use cms here. But I don't care. To me inches are more accurate and logical.] tank. A great set up I have found. Now I regret as such I never added any fert substrate to the tank. But oh well all is slowly growing. Now it may not sound like I am answering your question but I AM.

As I said I never added any fert to it. So it is just plain sand. Which is about 1-4 inches. Was 4 inches fully thick but my loaches have changed some of it around. So for filtration I have a Fluval canister 304. And that is all. It gets just water taken out every week and add. And the filter once a month. Tank is going good. Has gone through a great cycle. And has been very stable the whole time it has been running which is well over a year.

So all debbie in the tank I don't have much off. There is a bit around some logs but stuff all. But if I dig down into the sand it is slowly forming a great media for the plants. And it must be working because I don't know the exact name but I know it is a crypt is growing like mad. And most other plants have gone good in it.

The same has been done in all my tanks bare for my Rift tank which gets good cleaning as much as I can around the rocks.

Now with constantly gravel vac of the tank is okay in ways. You keep phosphates down. But you got to beef up the filtration. So for me I like the middle of the two. Now I do get small amount of phosphate but I don't care. I got a nice set up of SAE and BN which clean all up for me.

But then again that was very slowly getting less. And now I can't even seen much phosphate in the tank at all.

So I hope this has helped a bit.

mac

[Caryl]

I am not Phoenix44 or cricketman and do not run my system the same way but...

Because the gravel alone can't process all the waste, even though it can make use of it.

I rarely vacuum my substrate, have a heavily planted tank, average stocking level and never use fertilisers, CO2 or other additives.

A good sized filter will keep the water clear too.

The detritus isn't so much "trapped" in the filter but "used".

[Ice222]

I'm not certain on this but this is how I think it works. Decaying organic matter are good fertilizers, not only for plants, but also for algae. Phosphate and nitrate are also good for both plants and algae, but ferts contains other elements which plants use. You probably want the plants and not algae, so if you have excess phosphate and nitrate in comparison to what your plants need and use, you'd be promoting algae growth. Hence why some people use phoszorb and nitrazorb or whatever.

Additionally, in order to help your plants to out compete algae, they also need good water circulation, so that nutrients/ferts in the water are spread evenly to reach them all. If you don't have good circulation and some plants aren't getting the nutrients they need, algae may take hold.

As for why some people vacuum the gravel, I think it's because mulm can be unsightly and if your plants already have a rich substrate and/or root ferts. You might pref to gravel vac and opt for cleaner looking substrate. Or if you have sand substrate like me, I read that it's good to stir it from time to time to stop anerobic bacteria build up or something. If I'm stirring it and dislodging mulm that might end up in my filter, I might as well just vacuum it up to prevent it mucking up the filter (since my filter's nothing grand).

I'm not a very experienced fishkeeper yet so please correct me if I'm wrong guys

[Scottie841]

I take the simple option. I dont gravel vac because I am lazy and dont want to do it.

The plants are happy and the filter only got changed because I wanted to remove the carbon as it is not needed. It was 3 months and the flow was still as strong as it was on the first day.

In the tank amonia is 0 so not an issue for me

[Moya]

I haven't read the posts by cricketman and phoenix (I probably should) but here's my reasoning for what I do.

We use to use gravel as the sole biological filtration method in aquatics using the under-gravel filter system. This was wear a tray was placed under the gravel, with an air or water pump attached to it that was responsible for creating water flow through the gravel bed where the bacteria would live.

However we have come a wee way now, and have better, more effective/tidier ways of filtering! While gravel is certainly porous, and will contain many bacteria, it pales in comparison to the surface area available in the special biological medias you find in your external canister filters. More surface area = more bacteria = a better rate of fish waste being broken down into fantastic plant ready nitrate. The problem with relying on your gravel bed as your biological filter is that, as you mentioned, this is where some detritus ends up. This detritus breaks down into the gravel and can 'clog' the gravel, giving it even less surface area than it originally had! This problem of clogging is why you will always find the biological media in your canister filters pretty much near to last in the water flow. We use all the mechanical forms of filtration (sponges etc) first to make sure all the biological media is kept nice and free of big bits of grime, which would otherwise limit their biological capability.

Because we are not reliant on the biological capabilities of the gravel anymore, we don't have to be so thorough in removing the grime from the gravel; we can leave a nice bit of goop in there to fertilize the plants, and just skim the syphon over the gravel when we do the water changes to remove any of the more heavily soiled areas.

As to the phosphate/nitrate thing. I for one have fish I feed ALOT. Everytime I see them. Sometimes 8 times a day (they're discus). As a result I get lots of nitrates (yay!) for my plants but also alot of phosphates (booo...) that contributes to algae problems. Because of this I end up doing large water changes more to get rid of the phosphate than the nitrate (but phos-zorb helps too!).

Reading over this im not sure if I quite answered your question properly...but I hope it helps!

[John Rimbauer]

A couple of thoughts on this based on my experiences.

You can run a tank so lean that you exhaust the phosphorus and nitrate in the water. When you reach this point, the breakdown products from the debris on the gravel will be used as soon as they are released by bacterial activity. Vascular plants - i.e. most "plants" in an aquarium - have very efficient capture and transport mechanisms for nutrient compared to algae. So good circulation in the water will give the plants in a tank lots of opportunity to scavenge the liberated ammonia and phosphates.

Also, ammonia is more biologically available than nitrate as nitrate has to be reduced before the plant can use it for protein synthesis. Ammonia takes less energy from the plant to reduce, and as it is very soluble, is less work to transport. I'd suspect that it actually enters the leaves via osmosis rather than having to be transported via the vascular tissue.

So in a hypothetical semi-lean established tank, the plants would have less nitrogen (be that ammonia, ammonium, nitrite, or nitrate) and phosphate than they would like. When debris hits the gravel and begins breakdown, the products of that are captured in the waterflow and absorbed by the plants. As the non-soluble material builds up, the plants will extend feeder roots into it, or you may choose to vacuum it up.

Just my thoughts, no guarantees implied. :lol:

[Cricketman]

The bit I would like you guys to help me understand is - if it is good to have this detritus in the gravel, why would you want massive filtration which means more of it gets trapped in the filter and less in the gravel? While obviously the results of the breakdown of the detritus (NO3) is still available via the filter, why bother with massive filtration if the gravel is sufficiently performing the task? It sounds like you guys are not really using the filter mainly for it's biological capabilities?

Is the filter there (almost) purely as a water polisher i.e cosmetic value?

I can only speak for myself, but I use an overflow system before the water goes through my filter, in this overflow chamber (it is a box that goes down the corner of my tank and then out through a drilled bottom) I have filter wool and some plates that trap most of the large debris/detritus that would otherwise go into my filter (hell of a lot easier to change the filter wool/clean the plates than open up the canister all the time) . I use the filter mainly for polishing the water, removing floaties etc, but it is also useful for increasing water volume and giving extra surface area for bacteriological breakdown and metabolism.

It is also useful for water movement. one of the main things that you need to make this system work is high aeration of the water, also the more times you can "turnover" the water in your tank through the filter, the better. agreed putting an FX5 on your 20l nano is going to cause a mini typhoon, but in general, more filtration you can get, the better.

Also, as P44 said, if you have a bigger filter now, you wont need a new one if you decide to upgrade your tank at a later date.

I suppose that where I am going with this is, that if you have 'trained' the bacteria living in your gravel to deal with massive amounts of waste (more so than if you vacuumed weekly/fortnightly/monthly, then a biological filter is less of a requirement rather than more. Make sense?

In my (rather simple) mind, your gravel will be doing such a great job that you could run one filter with filter wool only (no biological media at all) just to ensure suspended matter is removed from view?

Filter wool gets clogged easily, so would deteriorate the efficiency of the filter. And whilst the gravel does do a great job, I still run the canister as a fail safe mechanism, and to breakdown things that get trapped there-in.

Also, if NO3 for the plants is so desirable, why have such large/frequent water changes?

NO3 is also desirable to algae. The bulk of plants only use a portion of the NO3, and usually they absorb is straight from the gravel. I don't think my water changes are large, but they are frequent. again for clarity and removing the excess NO3. also I just like water changes since I think of the water as going stale after a while. imagine being in a room with no doors or windows open. Pretty much the deal with the tank for the fish.

When setting up the gravel cycle, I do heaps of water changes to avoid the ammonia spike and nitrite spike that is part of cycling, but soon enough it gets going. water changes also dont disturb the gravel, just remove the released NO2 and NO3.

Something else I just thought of - if you are adding fertilisers to a planted tank why would you have Phoszorb and Nitrazorb in your filters? Essentially you are putting the fertiliser in to have the good bits removed. Also, the nitrates that are being created by the intentional leaving of fish waste, for the purpose of plant health, will also be removed by the Nitrazorb. I am a smidgen confused!

Like I said, the plants will absorb most of it straight from the gravel, I don't use nitrazorb, but I have used phoszorb.

phosphorous is rare in nature, even rarer in water. this is because it binds strongly to the earthen soils, and its dissolving in water is thus even rarer. it is also a main part of photosynthesis and is needed by algae to grow. With the phosphorous laden soils and fertilizers that are being used on farmland, there is a greater amount of phosphorous in our everyday water. I have had a phosphorous spike in my tank that I believe was caused by truck with phosphorous laden soil going past and the dust settling in my tank. caused a huge horrible algae breakout. Hence the PhosZorb.

NitraZorb can be used in the filter to remove excess nitrate/nitrite in lieu of more water changes, but I don't go down this route.

Its all about balance and testing your water to see what the various levels of NO2/NO3/NH3/NH4 and pH are like and see what is working and what is not. I have been doing it for long enough with this particular tank that I have it sussed.

Also I don't use nitrogenous/phosphorous fertilisers, I only add flourish for carbon and trace minerals.

Note that this system works for my community tank. I like it since it is all about being easy, and minimalist, whilst growing my plants better than ever. It is not a perfect system that is going to work for everyone, and i don't reccomend that everyone dump thier canisters immediately, it is all about a balance.

another point to think about.

Imagine a river in the wild: Constant high flow and water turnover, but the gravel/sediment is never turned over or vacuumed. Yet it survives and the plants/fish survive without major algae or problems. This is what we are doing in essence.

[fishplants]

Hi guys, thank you all very much for you time and effort in answering my long list of questions. It has been really good for me, and I am sure others, to see some of the theories and science that different people apply to their aquarium-keeping. My favourite quote so far is by Cricketman and it formed part of an extensive and informative post;

To me, this sums it up perfectly. Aquarium-keeping involves a lot of science but the art itself is not an exact science. Due to the huge number of variables involved in keeping an artificial eco-system in a tiny glass container, there is no black and white and no 100% right or 100% wrong answers.

As I have mentioned elswhere, what works for me is my 180l tank with a 10 year old 204, light pressurised CO2 injection, no phoszorb, no nitrazorb, no liquid fertilisers, 60w T8, weekly 35% warm water changes mainly for the Discus (and now fewer gravel vacuuming sessions!). This tank has been in balance since the blue green algae outbreak six months after setup, and the last 9.5 years has seen virtually no algae and healthy plants and fish. This tank is in balance and I am happy with the minimal work I perform on it, but as cricketman said, this setup may not work for others.

As I am typing this I am watching the Discus in my other tank, the adult Brown and adult Blue Turq are dancing around each other and have been acting rather odd with each other all week - maybe some romance is on the cards!

Just one last question Cricketman, you used the word 'aeration' in your post, did you actually mean 'adding air to the water'? Or did you just mean water movement? The reason I ask is that aerating the water removes CO2.

One last point, fish food contains varying levels of phosphorous. In a study I read recently, farmed trout were shown to excrete faeces containing 2.6% phosphorous! I have just looked at my dry food and was shocked to see that Tetra colorbits contained a minimum 1.5% phosphorous. The Nutrafin max flake contained a maximum 0.9% phosphorous. Something to keep in mind.

cheers

[Poecilid]

This discussion has been going on since power filters were invented. I ran tanks successfully for many years with no filters (just air stones for a bit of water circulation, and occassional water changes), by having heavy planting and not too many fish. When power filters came along, everyone wanted to pack in lots of fish, heavily planted tanks became less fashionable, fishfoods got richer and richer (great for the fish, bad for waste products), and shops started selling huge quantities of garbage for 'cleaning' tanks and 'balancing' water conditions. The argument about gravel bacteria vs filter bacteria is not the right one. The answer is simple; if you want high stocking levels, accept that you'll need extended surface area for filtering (biological and mechanical filters), will have to syphon out surplus mulm, and may even have to add chemicals (yuk). But that seems all too hard to me. I prefer to spread the fish around more tanks, and keep my workload down to the odd water change!

[raewyna]

Something to read - "Ecology of the planted aquarium" by Diana Walstad. She is a scientist who is also an aquarist. If you go to your local library it probably won't be there, but you can always interloan it. Tauranga has a copy.