Substrate change

[jbrown03]

I am about to embark on planting my aquarium . Unfortunately this is going to require changing the substrate in my tank. At the moment the substrate is purely pea gravel, which I intend to change to a combination of silver sand, quartz and a laterite based substrate with an undergravel heater.

I am concerned that I should change the substrate in a way that effects the tank as little as possible. I have read a web page or two that says that when changing the substrate it is best to change only half in one go, and wait a few weeks before doing the other half. The reasoning behind this being that a lot of the biological filtering in the tank occurs in the substrate. I find that a little hard to believe, this information probably being the result of the Chinese Whispers effect. I can't imaging a lot of water flows through the substrate of a tank that is not undergravel heated, and hence little of the substances that require biologically filtering would get in to it. I can also imagine that conditions in the substrate are rather anaerobic, and hence only nitrate converting bacteria would live there anyway.

Based on the assumption that the bacteria in the substrate are probably not very helpful to biological filtering, I am planning to change all the substrate in one go. Does anyone have any thoughts or advice about this?

 

[Allivymar]

Actually a goodly portion of the nitrifying bacteria are found in the substrate. Keep in mind they colonise surfaces, and there is a LOT of surface area in the gravel. Much of the detritus which isn't caught by the filter falls into the substrate, where it rots and is converted to nitrogenous waste. Theres a good food source for nitrifying bacteria down there.

So removing all of ithe substrate in one shot can affect the water parameters. It depends on how much other surface area is colonised by the bacteria; if you have a Bio-Wheel for example, the effect on water parameters wouldn't be as severe.

 

[Bearfan]

It will. You will be basically starting over with a little jump start.

 

[Guest]

Based on the assumption that the bacteria in the substrate are probably not very helpful to biological filtering, I am planning to change all the substrate in one go. Does anyone have any thoughts or advice about this?

When you assume something you make an ass out of u and me. Your assumption is wrong. If it were correct you would be fine. But it's wrong. As has been mentioned there is a massive surface area involved with even the first 0.5" of the substrate depth. But I'm more concerned about your use of a undergravel heater. If you are going to do any moving of crypts, swords, or many stem plants down the line the heater cables are going to give you no end of grief.

 

[TankGirl]

I can attest to the perils of changing out substrate completely in one shot, and that was on a tank with a Biowheel. However, I simply added a shot of Bio-Spira and all was well, lickety split!

 

[jbrown03]

Thanks for the replies. Lucky I asked, otherwise I would have been in trouble. I'm not looking forward to doing this.

 

[TankGirl]

I am assuming that you can't get your hands on Bio-Spira, so you will indeed need to be careful. Putting laterite into an existing tank is a trick in and of itself! Good luck, and let us know how it goes.

 

[oscarbreeder]

I have changed gravel in my 55gal tank before but done it as found here(I think) only changed half at a time waiting a week or so in between.
Everything was fine.
HTH

 

[jbrown03]

I am assuming that you can't get your hands on Bio-Spira.

What is Bio-Spira? I'm not sure I am not aware of it, but I might be able to get some. Presumably it will help bacteria growth?!

 

[Guest]

A simple Google search will turn up tons of information about Bio-Spira. Or you can go to http://www.marineland.com/science/nspira.asp and read about it. It actually does what many other products have claimed to do over the years. It basically instantly seeds the tank with bacteria to jump-start the nitrogen cycle.