Substrate replacement. Old Tank Syndrome

[fizzlefish]

Well the substrate in this tank has been around since 1998. This is the last thing in a quest to find my nitrate/phosphate factory. Now what my plan was to do is to remove all but maybe a 1/4 inch of its current substrate then add a inch over that. Reasoning is that the old will seed the new since i will be using dead sand. Does anyone think this is a terrible idea?

Added Info:
I currently have about 2 inches of sand on 1 side of the tank and about 4-5 inches on the other side due to a goby. I am using med grain aragonite.

 

[StirCrayzy]

I would siphon out the nasties from what's left of your old sand before adding more on top.
Whats left at the bottom of an old sand bed is not pretty, and once stirred up, is not what you should bring into another setup.

There is value in the old sand, because on the surface is where your bacteria reside.
I just upgraded tanks and used all of my old sand that hasn't been touched since 05 when I moved.
I rinsed it very well in some of the old water, and put another 50lbs on top in the new setup.
Not sayin it's the best idea, or that it's even better than starting clean, but I like my old crud and think it's worth saving..

I am curious though what type of nitrate readings were you getting, what are the equipments being used, and what remedies have you tried?

 

[sirrealism]

+1^

 

[DaveK]

First off, how big a tank are we talking about?

It's a lot easier to do something with a 30 gal tank compared to a 150 gal tank.

What makes you think that your substrara is the source of your nitrate and phosphate problems? It could be, but there are a lot of other possible sources. Don't rip it all up unless your sure.

Removing all but 14" would be a bad idea. These lower levels of your sandbed can contain a lot on anaerobic bacteria, and that's the stuff you don't want to dig up. If you are going to change your sandbed, remove a few handfulls from the top of the sand bed, siphon off the rest, and replace it with new clean sand, then add those saved handfuls to reseed it. However, as pointed out, the old sand does have some value. You don't want to lightly discard it.

 

[fizzlefish]

First off, how big a tank are we talking about?

It's a lot easier to do something with a 30 gal tank compared to a 150 gal tank.

What makes you think that your substrara is the source of your nitrate and phosphate problems? It could be, but there are a lot of other possible sources. Don't rip it all up unless your sure.

Removing all but 14" would be a bad idea. These lower levels of your sandbed can contain a lot on anaerobic bacteria, and that's the stuff you don't want to dig up. If you are going to change your sandbed, remove a few handfulls from the top of the sand bed, siphon off the rest, and replace it with new clean sand, then add those saved handfuls to reseed it. However, as pointed out, the old sand does have some value. You don't want to lightly discard it.

It is a 90 gallong with 40 gallon sump. 115g total water volume estimated.