Originally Posted by No CO2
I have a 125 gal 6’ standard tank that I plan on making a low tech/low light planted set up. No CO2 or excel, but I plan on using fluorite (w/some laterite mixed in?) and dousing fertilizer. I was thinking of running two Ehiem 2075 canisters (330 gal/hr each). Too much? It will be stocked. As of now the list includes: some corys, a rainbow shark, bala sharks, siamese algae eaters, synodontis cats and the rest to be named later.
I’ve got a 75 gal standard tank with about 3” of fluorite that I plan on transferring to the 125. I’d like to top it off with about an inch of sand. Would this work, or would the sand just work its way down through the fluorite? Would anyone suggest incorporating some laterite into the fluorite or is it not needed? What about a layer of peat moss on the bottom?
Any suggestions for lighting? It looks like two 36” fixtures is about the only reasonable option to go without spending a fortune on a 6’ light. I’ve read that the WPG rule breaks down on tanks larger than 75 gal.
To begin, welcome to Tropical Fish Keeping forum.
Now, on the substrate. Mixing different particle sizes will result, always, in the smaller at the bottom and the larger at the top. There is a normal water movement down through the substrate that speeds this along. So never mix sand with gravel.
On the Flourite and laterite, I would not waste your money. Several years ago I used laterite below a layer of fine gravel in one tank, and with the same plant species and identical lighting, fertilizing, etc. in three tanks, the plants were n o better for the laterite. This is an iron clay product, and when it first arrived on the scene it was the thing to have, but since then it has been shown to be only part of the entire nutrient balance and without higher light and other nutrients of (in my view) no value.
Flourite i also would not bother with. I have this as the sole substrate in my 70g, and here again the plants have not responded any better. It has been over 15 months now, and I intend to pull this tank down and replace the Flourite with play sand. Another issue with Flourite is the sharpness; I had to remove my corys, and even n ow when pushing my fingers into this it is still quite rough and hard.
Peat moss i have never tried, but this would be a temporary help at best, since the peat fairly quickly loses its tannins/nutritive properties.
My suggestion would be either natural fine gravel throughout, or natural sand. I use Quikrete Play Sand and now have this in five of my seven tanks, and soon to be in the sixth. Some fish need sand, but otherwise either sand or fine gravel work much the same.
On the light, I would suggest four 36-inch T8 tubes in parallel full length of the tank so you have dual tubes full length. I have the dual 48-inch T8 over my 5-foot 115g and it works well. This gives low to moderate light, which permits a number of nice plants. The WPG "rule" is not really relevant these days, with all the newer more-intense lighting. When we used the larger T12 tubes in Grolux back in the 1980's, wpg had some significance. But the present T8 tubes are much more intense light in the same space with less wattage, so this is unreliable. And T5 is a much higher level again.
I have a series on a basic low-tech approach stickied at the head of this section of the forum, entitled "A Basic Approach to the Natural Planted Aquarium" in 4 parts that might tie all this together for you. And the photos under the "Aquariums" tab below my name on the left illustrate the results.