Water Changes


New member
I have been in the aqua world for a while. I have always done water changes on a consitent basis. FW twenty percent every two weeks and SW same but every week. When I do a water change I syphon water into a 5 gal bucket while syphoning up the bottom of the tank, sifting through the sand and sucking up the detritus in the substrate. I have always had success with my tanks but never tried the following technique.

I have recently heard someone say that on a well established tank that syphoning the detritus from the substrate would destroy the tanks balanced system.

So please give me your opinions tell me your experiences and what you do as well. Thank you ahead of time for your posts.


In Memoriam
Bacteria in the sandbed break down the diatoms and produce Hydrogen Sulphide in the process. By employing the above technique, you run the risk of disturbing those Hydrogen Sulphide pockets that may have formed in your "dead spots."


Team RC
You are correct if you keep a deep sand bed or one that you'd like to keep 'alive'. Your cleanup crew should do an ample job of keeping your substrate tidy without the risk of destroying the nitrifying bacteria. Unless of course you keep some gobys or starfish. :) I would advise against vaccuming the substrate unless you have a real problem with algae or something. Which again, hopefully, your cleanup crew will make quick work of.

Now, if you have crushed coral as your substrate... that's a different story. Is your sandbed a fine aragonite or crushed coral?


New member
I agree with affan.

So long as your just dumping the water out it will be fine for h2s i suppose. I think that syphoning the sand will result in O2 killing off denitrifying bacteria.

Some people syphon, some people replace their sand every six months. Some people dont touch it.

Why not make a new thread with a poll, put in somthing like what do you do to your sand?

-syphon it
-stir the top layer
-syphon half leave the other for next week
-replace the sand evey so often
-cover it with new sand
-no sand at all bb

Actually I will do this for you :D see what happens.


New member
My substrate is fine aragonite. I only vaccum up the parts that are not covered by LR, obviously. I do not have much LR maybe 50-60 LBS but it is spread out so I end up syphoning about half of the substrate. Also I have about 1-2" of LS and am going through a long algae problem.


New member
I have about 5 inches of aragonite sand in my 55 and my 150.
The 55 has been set up for 23 yrs and the 150 for 11 yrs.
I always siphen the sand when I do a water change.

I try to just siphen the top layer maybe an inch or 2 and yes like others can only siphen where the rocks arent on it so prolly not even half the actual sand.
I havent had a problem so far. IMO if you never siphen out the detritis your going to have problems. I don't think the clean up crew can handle all of it.
I have a few times in the 23 yrs removed the rocks and siphened all the sand in my 55 but only maybe 2-3 times.
Once I went BB in my 55 about 15 yrs ago and it did'nt do well so added sand again after about 6 months.

Just the way I do it. Everyone has different ways of doing things.