Algae probs, sand out or in?

[lcheesman]

Hi all,

I have had continuing algae problems for a long time. I have with the help of kind folk here at reef central ruled out most possible causes. However, recently it has been pointed out to me that my 1.5 - 2 inch sand bed could be causing nutrient problems...depite having 0 nitrate and 0 phosphate (well on the test kits anyway).

I intend to end up with around 90% sps in this 250 gallon.

The substrate from what I have read is in between a non active 1/2 inch bed and an active 3 inch + bed. So I am concerned and convinced that the detritus acumulating and not being broken down is causing the problem.

The bed is 2inchs of mixed fine sand and aragonite, some of it is clumped and stuck together.

What should I do, get it outta there and put in 1/2 inch or fill it up to 3 or 4 with more fine sand?

if so how do I go about doing either of these?

I have a few creatures that like the sand, coris wrasse, crabs, cortez ceriths etc.

 

[fishdoc11]

Is this "hair algae" that's pretty much out of control?
It's very possible the sandbed is full. Removing it and adding more(whether it be shallow or deep) is a much better idea that placing new sand on top of what you have IMO. IME algae will sometimes use up nutrients before they show on a test kit.
Using a siphon hose with the wide part removed and a stiff narrower section of hose added to siphon out the sand works well.
Chris

 

[DaddyJax]

There are plenty of people who believe that ssb need to be recharged. This consist of removing the ssb and replacing it with new live sand. I have done this in my tank and it showed a little improvement. The best method ime is to syphon out the sand at every WC and stir the sand every few days to allow the mechanical filtration and skimmer remove trapped detritus.

 

[lcheesman]

At the moment it is hair algae and a it of cyano, there have been other types also. tank has been up and running for over 2 years. I was thinking of getting it all out and puting only 1/2 inch of coarse sand.

Is there anyway I can be sure that the problem is being caused by the 2" sand bed?

 

[fishdoc11]

Is there anyway I can be sure that the problem is being caused by the 2" sand bed?

If you have tried everything else(RO/DI, good skimming, water changes etc....the list goes on) that's the only thing left
At least that was my experience.

I also tried a shallow course sandbed and the problem with that was after a while the nitrates start to creep up. The problem is, even with regular siphoning of the substrate, you will get detritus buildup under the rocks that you can't get to without removing the sand again.

Chris

 

[lcheesman]

fishdoc11,

once I remove the existing substrate what would you recommend I replace it with? I wan't to only have a scattering of sand for effect I think. My live rock..about 140kg should take care of the biological filtering?

 

[Froggy]

Can you give specifics about your setup? What skimmer, water change schedule, filter socks used / changed. How often? Anything else hooked up on the system that can become a biological filter on it's own by trapping detritus and can lead to problems. Stocking load ?

There are several successful systems that do regularly change their sand beds by regular syphoning and replacing the bed every six months to a year. This may be a fine option for you. Your sand bed may not be the problem though. I am just wondering if maybe other things may be at play that are causing problems beyond the sand bed.

I began having problems with nuissance micro algae in my 75 gallon reef and thought about removing the sand and either replacing with a new bed or going barebottom. Instead of doing either, I improved my skimming with a big upgrade at skimmer by replacing a Remora hang on with an in sump Euroreef CS 6-1 skimmer. My algea problems have stopped and all of the problem algae has almost completely dissappeared and has not reappeared. My system seems to be in good balance now and coral coloration is greatly improving as well. This is just a bit of personal experience that I had. Just something else for you to consider before removing your existing bed.

 

[fishdoc11]

Good points froggy

A very thourough cleaning of the sandbed is another thing to try if you haven't allready. One problem with that is if the sandbed is saturated it's likely the substrate is saturated with nutrients(mainly P) and will release them back into your water column.

Your live rock should provide more than enough filtration. It's really up to you what you decide to replace it with if you do. A shallow bed will require more maintenance than a DSB. I have seen people that place an abundance of stirring critters such as cukes, sand sifting stars and nassarius and have luck with that as an alternative to weekly or biweekly siphoning. If I was to do a SSB again I would probably try a fine substrate such as Southdown if flow would not be a problem with diplacement. The thinking being that a finer substrate has less "gaps" between particles and will not facilitate movement of detritus into it as much as a course one.

Chris

 

[lcheesman]

Hi, thanks for the replys thus far.

There is nothing else that could be acting biologically apart from the sand and live rock.

Skimmer is a deltec ap850 which works very well, I really dont think that is in need of upgrading.

water changes 25 gallons 3 times per month at the moment.

I have today siphoned 1/3rd of the substrate out on the right side of the tank. phew-ee what a stench. The 30 gallons I pulled out when siphoning the sand out was disgusting, the water was very brown...I could'nt see through it, but I managed not to kick up much into the main water column.

I can't see that having that lot in the tank is doing it any good at all. There were some areas on the rocks that were submerged in the sand that were black..hydrogen sulphide?

I am going to siphon the rest out over the next 2 weeks, blow the rocks down with a power head and siphon some more until there is no detritus left. I will leave as bare bottom for a few more weeks whilst I vac the remaing crud. I'm not bothered about putting anything back in yet.

I have 2 x 3500 lph returns and 2 x tunze streams both on 24/7 kicking out 12,000lph each.

I have my fingers crossed that this is going to work for me in the end...does it sound like it could be the problem?

 

[fishdoc11]

It does indeed sound like the sand is the problem from your description. Be carefull about the black spots. Running copious amounts of carbon, cranking that Deltec up, running a filter sock and water changes will help with anything you "dig up" but I'm sure you allready know that
good luck Chris