Reef Tank Substrate - change it?

My tank has been set up for more than 18 months now. Its a fairly large tank and has a LOT of live rock. Many of the corals have become well established and anchored on the main aqua-scape pieces.

I have coarse crushed coral as my substrate...again lots of crushed corals....in the hundreds of pounds.
I have read a lot of posts on various sites that "poo-poo" crushed coral and endorse the use of finer type sands. Personally (being old-school) I like the looks of the crushed coral bottoms...despite the fact that its not natural to reefs as is sand...(hey!... I like what I like). But more importantly many posts warn of impending Nitrate and phosphate spikes with crushed coral and I want to do the right thing for the tank.

With that said, I do not have nitrate or phosphate problems... In fact, I even have to dose KNO3 just to get a trace of nitrates for my corals to color up.

Should I make the HUGE effort of replacing as much of the crushed coral as I can? It would only be about 30 to 40 % of the substrate volume. The remaining 60 to 70% is well buried between the aqua-scape and has even solidified into a mass that resembles more of a solid chunk of live-rock on the tank bottom. I suppose that this is the result of bacterial action that has forced the individual pieces of coral to fuse.(?)
Is there any advantage to partially replace this substrate with finer coral sand?

Thanks in advance for your input.

V.

 

From what I've learned "if it's not broken, don't fix it". If it's working for you and you've managed to keep it working then why mess with it? I think it would do alot more hurt to mess with it.

 

If you're worried about your substrate gathering more detritus, then I would just try and siphon-clean your substrate when doing a water change. I wouldn't worry about what you can't reach.

I like my crushed coral, I can blast the flow and not have sandstorms. However, I do understand what people like and if you must change out your substrate, only do portions at a time. You are creating an environment that "could" be harmful to your tank. If you disturb a dirty substrate without siphoning it out straight away, then your tank is not going to be happy.

Good luck!

 

I agree with why change it? if it's working for you - disturbing it could create a lot of problems. Zesty's advice is good, to just siphon small sections when you do a water change unless it's a deep sand bed then just siphon the top portion

 

Thanks everyone for the good advice. I like the looks of my crushed coral so i will keep it and siphon off the top layer during maintenance. I'll keep an eye on phosphate and nitrate levels as the tank gets older.

Thanks again!

V.

 

Good thread guys. I am setting up a display reef with a display refuguim below. I read the thread bare bottom vs sand. Good thread, I am thinking of putting Marinepure 1"x8"x8" ceramic blocks under the sand in the refugium. Have some time to think about it, I have to build a custom stand for it, still in the planning stage. but anyways again good thread and thanks for the info people.

 

I wouldn't waste my time. Those blocks are intended for use in higher flow areas and are frankly not needed. The sand and lr in your tank provide ample places for the biofilm to form. You cannot stockpile bacteria its population is limited by the food available.

 

My reef uses dolomite which is somewhat like crushed coral and my tank was set up in 1971. No problems yet, but I run a reverse UG filter.

 

I used crushed coral in my 55g and then learned its not a favourite. I did not replace it. I made sure I had ample flow to keep crap off the substrate, i had nassarius snails, and I lightly vacuumed the crushed coral with water change.

I liked it, I never had any issues with Ca or alk, no phos issues. I ran into nitrate issues but that was due to filter sponge and overstocking.