[Tihsho]

So while I had some down time at work I started thinking about substrates for a new tank. I broke it down to the simple fact of good substrates provide nutrients first, buffer second, and look good third. That being said I started to think about hydroponics and how nutrients are fed to the roots via a liquid. In an aquarium this is... well impossible. How can you feed liquid to roots without saturating the entire water column?

Thinking about this a little more technically I figured there might be a way to do this to remove the need for specific substrates (i.e. plant focused substrates.) Let's look at this like layered planting. Base layer = filter floss. Middle = coarse (not huge, but not sand) pool filter media. Top = non calcitic sand. The logic behind this is to saturate the filter floss with nutrients, be it something bottled off the shelf, or something else that is powdered but dissolves slowly. You might be thinking, "Well how do you re-saturate it?", simple, hypodermic needle/fine eye dropper syringe.

After reading through a lot of MTS and MGOPS threads I see a lot of complaints about the mess of replanting or some fauna kicking up the cap exposing the soil. Overall I was looking for another solution besides off the shelf planting substrates and root tabs in plain aquarium gravel.

Thoughts?

 

[Mrnbo]

How do you control the rate at which the nutrients will dissolve out of the filter pad?

 

[lauraleellbp]

Filter floss (or anything comparable) would make it pretty much impossible to move plants around without either totally tearing up the floss or destroying plant roots.

Most people get around the issue by using root tab ferts.

IME, MG is only messy for the first few days anyways.

 

[Monster Fish]

Root tabs would be easier IMO.

 

[lochaber]

I'm not sure injecting liquid ferts into the substrate would be a great idea.

Since it's liquid, some of it would immediately start diffusing through the substrate, and reach the main tank volume pretty soon. And since you are doing this to 'recharge' the substrate, I assume the ferts would be of a much higher concentration then what people typically use for regular water column dosing, and possibly harmful to the critters.

If you did want to do something like this, you would probably need a more impermeable layer above the 'sponge' layer. Maybe something like bentonite clay? I think that's what they use to line landfills and ponds, although I'm not sure it would be too effective sealing twixt water/water (as opposed to water/soil). In landfills and ponds, it works good as a sealant since it greatly expands when wet, so it's packed in dry, and when it gets wet, it sorta 'self seals'.

And instead of filter floss, maybe just use dirt, or coconut coir.

Anyways, I think periodically adding root tabs is probably a better approach - they will be slightly slower to dissolve/break down and release the ferts, which would also help to avoid poisoning the water coloumn. As to insertion, you could try something like a straw or pen tube, with a chopstick/skewer/rod set in it to act as a plunger, set it so that it leaves a gap at the front that will hold the root tab or whatever. Stick the whole thing into the substrate, push the plunger as you remove it, and slowly draw it back out. I haven't tried it myself, but something like that (or maybe just holding a rood tab in long tweezers?) might work for getting them in place without too much tank disturbance.

 

[dmagerl]

I have injected my EI dosing into the substrate using a turkey baster syringe. It has a much bigger needle than a regular syringe and is easier to inject into the substrate.

I did this when I ran out of root tabs and took a few weeks to reorder. I just took the dry ferts and mixed them with about 100ml of water and injected that into substrate all around the tank. Eventually it ends up in the water column but thats what EI dosing is supposed to do anyway.

 

[plantbrain]

Sounds more complicated than it needs to be. You can not worry about ferts in the water column , it's rather obvious that is does not matter one bit.

Sediments like ADA AS are messy, but at least homogeneous. So you can simply learn to make less mess when you plant and replant with soils, do water changes after the replantings etc.

A day or so, they clear up fine.

So that's 2 issues that are easily solved.

My tank uses soil + EI dosing: I seem to do okay.

 

[Tihsho]

Sorry I didn't respond sooner, I forgot to subscribe to my own thread. I knew this would bring up a lot of negatives, but again this is a spitball idea.

How do you control the rate at which the nutrients will dissolve out of the filter pad?

This is hard to do with liquid ferts in an aquarium. The hopes were to find a way to layer the substrate so the ferts saturated below the thickest cap to prevent leeching into the water column.

Filter floss (or anything comparable) would make it pretty much impossible to move plants around without either totally tearing up the floss or destroying plant roots.

Most people get around the issue by using root tab ferts.

IME, MG is only messy for the first few days anyways.

I did start to consider the issue of the floss being a thick medium to which roots would cause some serious issues once plants get established after posting this. This is a very valid point

This was thought up to replace root tabs. Yes they are easier, but you cannot supplement specific ferts with the tabs I'm familiar with. Most are general supplement tabs.

Root tabs would be easier IMO.

Please see the response to lauralee above.

Since it's liquid, some of it would immediately start diffusing through the substrate, and reach the main tank volume pretty soon. And since you are doing this to 'recharge' the substrate, I assume the ferts would be of a much higher concentration then what people typically use for regular water column dosing, and possibly harmful to the critters.

The diffusion through the substrate would depend on the viscosity of the ferts vs. the viscosity of water. The more dense the fluid to lower it would settle. Again, as mentioned above, the thought was to layer some substrates ended with a thick cap to prevent significant leeching as well as reduce water flow through the substrate.

If you did want to do something like this, you would probably need a more impermeable layer above the 'sponge' layer. Maybe something like bentonite clay? I think that's what they use to line landfills and ponds, although I'm not sure it would be too effective sealing twixt water/water (as opposed to water/soil). In landfills and ponds, it works good as a sealant since it greatly expands when wet, so it's packed in dry, and when it gets wet, it sorta 'self seals'./QUOTE]

For the sake of research I’ll look into that. I’m just curious on this concept since soil’s nutrients don’t last forever. It would be neat to find a substrate that could have nutrients replenished as to not having to tear up a tank once the nutrients are depleted (obviously years down the line if done right) or punch holes through carpets for tabs.

And instead of filter floss, maybe just use dirt, or coconut coir.

If it were the fibrous coconut husk media, that might work. The coconut husk substrates used in terrariums and vivariums is soil like and very fine, like fine soil.

Anyways, I think periodically adding root tabs is probably a better approach - they will be slightly slower to dissolve/break down and release the ferts, which would also help to avoid poisoning the water coloumn. As to insertion, you could try something like a straw or pen tube, with a chopstick/skewer/rod set in it to act as a plunger, set it so that it leaves a gap at the front that will hold the root tab or whatever. Stick the whole thing into the substrate, push the plunger as you remove it, and slowly draw it back out. I haven't tried it myself, but something like that (or maybe just holding a rood tab in long tweezers?) might work for getting them in place without too much tank disturbance.

Again, this concept was to remove the thought of root tabs and selectively supplement specific nutrients.

Sounds more complicated than it needs to be. You can not worry about ferts in the water column , it's rather obvious that is does not matter one bit.

Sediments like ADA AS are messy, but at least homogeneous. So you can simply learn to make less mess when you plant and replant with soils, do water changes after the replantings etc.

A day or so, they clear up fine.

So that's 2 issues that are easily solved.

Complicated, yes, but again this is a concept idea at this point. Agreed the style and finess used behind methods of planting/removing in a soiled tank can be perfected to solve this, but the point of the thread was not to have a “soil is better than this” discussion. Gorgeous tank by the way.