Saltcorner
By Bob Goemans
By Bob Goemans
Hi Bob,
You helped me out some time back so I thought I'd ask you a couple of more questions. First let me say that I have all of your four booklets and look forward to "Sand-Mail" every month.
Around the end of 2000 I set up two tanks with plenums, a 37 and a 125. Both are 24" tall so I still have a good water height. I built the plenums exactly to your specs. Two 2" layers of sand separated by doubled window screen. Thank God for that because my first question has to do with a now mature female tomato clown who has taken it upon herself to dig for China. I believe the pair is going to spawn soon, she has built a nesting area and exposed the dividing screen, a circle about three inches across. Is this going to have an adverse effect on the plenum?
Next, after about one year I had terrible algae problems in both tanks. I know there are many factors but I just couldn't stand how dirty the sand was when I poked around in there. Is it supposed to look like that? I vacuumed the entire upper sand layer in both tanks in January and both have been very clean and pretty much algae free ever since. Did I do the right thing? (seems like it) It was a major chore to do the 125 and I wouldn't want to have to do it again, not even yearly. Had to remove all fish, corals and 100+ pounds of rock!
Final question: The aragonite has settled/packed/dissolved into a total depth of only 2.5". Do I need to build it back up? Can I do this simply by adding more right on top, perhaps a little at a time?
I know you are a busy guy but if you get a chance I would appreciate your advice. Thanks in advance,
David.
Hi David,
I do have to question why you placed two sheets of screening midway in the bed, as one would have been sufficient. As for your questions, the clownfish is allowing slightly more oxygen into the surrounding area, which increases the amount of nitrate being produced in those areas and of course, decreases the amount of efficient denitrification in some adjacent areas. Yet, I doubt its enough to affect the entire system and/or the plenum space itself since there remains about two inches of sand above the plenum space. If anything, there might be a slight rise in nitrate level, but that should pass once the depression closes.
I recommend that it's necessary to vacuum the bed surface once a month. Those who say never vacuum are incorrect - would you not ever dust your house!
And the depth question is yes, you have to add new aragonite when things start to look a little lower than a 4 inch bed. I have dumped some rinsed aragonite through a length of PVC pipe to various areas and then raked it with a homemade long handled acrylic rake to spread it out. Worked for me!
Hope this helps,
Bob
