[GoinSalt]

I currently have about 1" sand bed and am plagued with brown algae and cyno.

If I upgraded to a DSB (3-4") would this help with the algae blooms?

If so, how do add the sand? All at one time or a bit at a time?

Nate

[Ninong]

If you want to add additional sand to an existing sand bed, you should add it gradually, about 1/2" additional perhaps twice a week until you get up to your desired depth. Adding it all at once could cause a dieoff of the upper layer critters in your existing sand bed, assuming you have some.

If you have only a 1" sand bed at present and it doesn't have much in the way of microcrustaceans and polychaetes, you might want to take a chance and add the new sand all at once. You could even remove your fish and live rock to a separate holding container for several hours while you do this. I understand from your other thread that the only coral in your tank is a single Ricordea rock.

A 3"-4" sand bed of fine particle sand would provide much more filtration capacity than what you have there now, which is virtually nothing. Whether it solves your nuisance algal blooms is another question altogether. Assuming that you are talking about persistent diatoms, then it's possible that your tapwater contains silicates. Your nitrate readings of 15-20 ppm are not exceptionally high but since you are using tapwater, you might have silicate and phosphate that you are unaware of. Maybe. Maybe not. Getting that R.O./D.I. unit will definitely help.

I don't know where in Northern California you are but there is a gigantic difference between San Francisco's water (which is snow melt from Hetch Hetchy) and water in the East Bay or the Central Valley. Your local water district could mail you a copy of their most recent federally required water analysis report. That would tell you a lot about your tapwater.

[GoinSalt]

I live in the East Bay. I've been looking at the most recent analysis and there is no mention of silicates or phosphates. They have TDS listed at 270.

i am, however, using just regular silica play sand. The HD and Lowes around here don't carry the Southdown brand. Could that be the problem?

[Ninong]

Silica sand should not cause problems if it is pure, uncontaminated quartz sand. Pure quartz sand doesn't dissolve in saltwater but feldspar and other silica compounds do. This topic always starts heated discussions on the boards because someone will post that they are having problems with diatoms and people will ask them if they are using silica play sand or not and if they are, then some people will tell them that's their problem and others will pop up and post that they have been using silica play sand for years with no problems at all. Both sides could be correct.

All I can tell you is that Dr. Ron Shimek insists that there is nothing wrong with using silica play sand for a DSB. Most people agree with that position but a few do not. I probably fall into the group that thinks that it might be risky to use silica play sand and for that reason I wouldn't want to use it myself. Check out these photos of aragonite sand and typical silica sand taken with a microscope: http://www.inlandreef.com/Testing/SandPhotos.html

After seeing those pictures, I just can't bring myself to choose silica sand over aragonite sand regardless of the cost savings. I think that's a decision that you have to make for yourself. If you were not having any problems at all with your present 1" silica sand bed, I would say to just go ahead and add some more until your depth was at least 3" but since you are having problems with diatoms, you might want to consider removing your existing sand bed and starting over with aragonite. I believe that's what I would do if I were you.

P.S. -- I lived in SF for several years. I also lived in Castro Valley (Palomares Hills) and Tracy for a few years and I can tell you that the water in SF was much better than the water in Castro Valley and the water in Tracy sucks!

[GoinSalt]

I actually live right between CV and Tracy -- in Livermore.

The funny thing is, I used the silica sand because, like you said, it was way cheaper than buying x-amount of the "live sand" sold at the LFS for $20 a pop. I've seen that link previously and the silica sand looks like it would hurt!

I recently found a "warehouse"-type store in Concord. While the prices for their corals may be a little high, I noticed they had 50lb. bags of crushed coral sand for around $40. It comes in different granule sizes -- from standard "crushed coral" to sand. I think I'll get a couple bags of this and change out my existing sand bed. If nothing else, it will at least LOOK good for a couple days/weeks until the algae returns!

If I do go this route, should I move the LR or just put the sand around it?

Nate

[Ninong]

Originally Posted by GoinSalt

I actually live right between CV and Tracy -- in Livermore.

Livermore!

Your water's radioactive!

Just joking. I used to work in Pleasanton!

I recently found a "warehouse"-type store in Concord. While the prices for their corals may be a little high, I noticed they had 50lb. bags of crushed coral sand for around $40. It comes in different granule sizes -- from standard "crushed coral" to sand. I think I'll get a couple bags of this and change out my existing sand bed. If nothing else, it will at least LOOK good for a couple days/weeks until the algae returns!

The only crushed coral that I have ever seen is a large particle size. There are various opinions on the best particle size, or mix of particle sizes, for a good DSB but most people would not use anything larger than 1 mm. In fact, the most common recommendation is that you use no more than 10-15% of grains in the 1 mm size and the rest much smaller particles (sugar sized and smaller).

If I do go this route, should I move the LR or just put the sand around it?

Either way. That's one of those personal preference decisions. The main thing is that your rock structure should be stable one way or the other. How you achieve that is up to you.