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Caliban07
Aquarium Advice Addict
Yes, under gravel filters. They’re very easy to set up. A simple youtube video would help you with that.
https://youtu.be/d4oqFXC76xk
17:30 minutes onwards.
One of the comments cracked me up. So very true and enlightening.
‘Let's talk about mulm. Yes, mulm does build up under the plates of an undergravel filter. But is that a bad thing? For a fish only tank, my answer is; maybe - if you neglect your water changes. For a planted tank, the answer is a big, capitalized, NO. Let me explain:
What is mulm? Where does it come from and how does it get under the filter plates? Every tank contains some mulm. It will be there until someone breeds a fish or invertebrate that doesn't poop and makes a food that won't decompose if it the doesn't get eaten . Mulm is decomposing organic matter. It originates from three sources. One, poop from fish, shrimp, snails, and any other aquatic animal you have in your tank. Two, uneaten food. Three, leaves, stems, and other plant parts that break off and die. All of these things are heavier than water, so they naturally fall to the bottom of the tank. Even before they fall, microorganisms living in the tank start to work on them. If there are any gardeners out there, this will sound familiar, It is exactly what happens to the stuff you throw into your compost heap, and the end result is the same thing- humus. Yes, mulm is aquatic humus, and it has the same benefits for aquatic plants as terrestrial humus has for your garden and potted plants. As the stuff decomposes, it breaks down into finer and finer particles and drops through the spaces between grains of gravel until it reaches the solid bottom of the tank. If there is no undergravel filter, It would still find its way through the substrate, just not as quickly. As the mulm decomposes, it releases the minerals stored in the food or poop back into the water. If the substrate is filled with living plant roots, it is quickly absorbed and used by the plants. If there are no plants present, that is why every sensible aquarist does water changes and gravel vac. The mulm will decompose, and the minerals will be released, regardless of the filtration system used. Whether it happens in the sump, the canister, the sponge, the sand, the gravel, or the floss is up to you and what kind of filter you use. In an undergravel filter, it happens in the gravel or under the plates where it can be easily be absorbed by the plants.
Another, seldom mentioned, benefit of undergravel filters is their effect on the oxygen - carbon dioxide cycle. Everyone knows about photosynthesis and how plants turn CO2 into O2. Most know that under bright light in a heavily planted tank, this can result in over oxygenation and a deficiency of CO2. What is less well known is that this process stops at the top of the gravel. The roots of plants do not receive any light and do not perform photosynthesis. They must absorb oxygen and release
CO2 or die. By circulating water through the gravel, UG filters bring oxygen down to the plant roots, and move the carbon dioxide produced by the roots up to the top of the tank, where the leaves and stems can use it in photosynthesis. One result of this is that with an undergravel filter, you find that the substrate is filled with a luxuriant growth of clean white roots. This is particularly obvious with Amazon sword plants, which will send huge masses of roots down through the filter plate and into the mulm below.
I will always use undergravel filters, and if they stop making them, I will make my own out of cpvc pipe. Don't worry about the haters. Hate is the result of ignorance. I know that the UG filters work and so do you.’
