Changing substrates

Juthunter28

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May 11, 2004
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My substrate is a gravel and marble mix, and i want to change it over to a fine gravel, but my tank is stocked and i dont have anywhere i can put them while the tank re cycles. So, i was wondering if i could change over half the substrate then change over the other half after the first half is in the tank for say 2 weeks to give it a chance to get some bacteria build up on it. Does this sound good? It is a 45 gallon tank. thanks
 
Not to hijack Juthunter's thread, but how long would the filter need to have been going to have a sufficient amount of bacteria for switching all the gravel at once?

I'm interested in changing my gravel as well, but don't currently have a filter going in my 5 gallon tank. :)
 
Originally posted by Rava
Not to hijack Juthunter's thread, but how long would the filter need to have been going to have a sufficient amount of bacteria for switching all the gravel at once?

I'm interested in changing my gravel as well, but don't currently have a filter going in my 5 gallon tank. :)

The safest way to change a substrate is....

Remove about half it and place it in a pair of tights (think its pantyhose to you guys/gals in the US) and fill the space with your new substrate. Put the tights full of the old substrate back in your tank aswell. Give it a few days and then remove the tights containing the substrate and dispose of the contents. Put the other half of substrate in the tights and put the rest of your new stuff in, again put the tights with the old substrate in and give it another few days. Depending on how brave you feel and how big your tights are you could do it in one on indeed smaller jumps

It may look a little ugly or indeed sound a bit silly :) BUT...

Doing it this way should minismise if not elimate any risk of problems, just incase your filter isnt quite established enough to cope as in fairly new (<6months) tanks there are significant bacterial colonies in your substrate.

Hope that helps :)

EDIT: Sorry forgot to explain the method behind the madness :). By putting the old substrate in pantyhose stops in mixing in with your new stuff and possibly spoiling the look of the new substrate. The reason behind using nylon is its no absorbant, wont effect your water parameters and allows water flow, so the bacteria (if any) in the substrate can still do there job :)
 
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Your filter should have sufficient bacteria cultures if your tank is completely cycled. Juthunter I've done this and it's a great big pain!! May I ask why you are changeing the gravel? If you have plants in your tank it is probably not a great idea to swutch to a smaller substrate because plants do best with "pea sized" gravel. If you are still sure you want to change your gravel it is not anything very difficult just long and laborious. What I have done is start by bagging your fish (if you don't have fish bags and elastics go to your LFS and they should help you). Set them out of the way in a cooler with the lid on is best because it stops them from being stressed and helps keep the water tempature consistant. Then do a good gravel cleaning (I mean really good) I've done up to a 50% change before I got all the gunk out of the gravel. Try not to stir up the water as much as you can as this makes it easier to pick out the gravel, and quicker to put your fish back into. Now the hardest part it scooping all the substrate out, if you do not need to get ALL of it out then don't worry about evey piece, but if it's say colored and your going to a natural color, it's gonna take a while. Also if you have a acrylic tank you will want to go in by hand before scooping out the gravel and gentely move the gravel from the sides of the tank so it doesn't scratch the sides. (if it's glass you don't really have to worry). I have found that the best thing to dig the gravel out with is just a fish net (but don't be too suprised if it breaks!) becasue the watercan easily flow out of it and you can also squeeze some moisture out as well. Then it comes time to put your new substrate in, the only thing I can say about this is to rinse your gravel whether it has been in a tank before or not. then scoop it back in the way you took the old gravel out.(this way it doesn't disturb the water too much. Then fill your tank back in, and get your water perameters back to where you want them, wait for the water so settle, do another gavel cleaning. and when all the crud is out put your fish back in, but don't forget to acclimitize them. That's about it, not rocket science, just a pain it the butt to do! Good Luck!
 
Ditto. I hate to have nothing to add but that, but I basically did the exact same as what vato suggested a few months ago, but in a 10g.

The only wrinkle is that I didn't take the fish out. I changed the gravel in 3rds. Remove 1/3 from the tank, spread remaining back. Repeat. In 3 weeks, you're adding the new substrate.

Lots and lots of gravel cleaning. It was cleaning before and after each removal, mostly because I found that I could never get it quite clean enough to keep the water from clouding.

It did stress the fish though, so vato's call of putting them in bags (or other tank(s) if you've got them and room in them) is a good one. Two of my swordtails had a short bout with some kind of infection. One recovered like there had never been a problem. One, not so well, but that one also survived from the beginning of my fishkeeping, i.e. general ignorance of cycling, overstocking, ammonia, nitrite. In any case, she wasn't in great shape to start with. Fair warning though.
 
I think vato's technique is great, although when I've done it I put the fish in open Rubbermaid tubs that I keep handy for just such a purpose.

If you have sufficient filtration that's been on the tank, removing the gravel really shouldn't cause a problem. In fact, I've set up many new tanks by transferring the fish and filters only from an established tank to a new one, without ammonia/nitrite spikes.

I'd still check ammonia and nitrite after the switch, but you should be OK.

Good luck,
Jim
 
Dumb Question

This may be a really dumb question, but I am new at this and want to make sure I understand this well so I don't hurt my fish.

You say that the filter should have enough bacteria on it sufficient to keep the tank from spiking? So it is what is on the outside of the filter not the filter netting on the inside?

My tank is only 3 months old and is cycled. I also want to change from a colored substrate to a natural color.

Thanks for your help.

The only dumb question is the one not asked.
 
Re: Dumb Question

Originally posted by ckeck
You say that the filter should have enough bacteria on it sufficient to keep the tank from spiking? So it is what is on the outside of the filter not the filter netting on the inside?

I don't think I understand that, but here's what I think you're looking for:

Nitrifying bacteria need a constant supply of oxygen and, not surprisingly, ammonia and/or nitrite. Translation, they colonize areas with a) high surface area and b) water movement.

This mean filter media. Pumped water provides new oxygen and food to the bacteria, all you need to do is provide them with the surface area.
 
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