why does the sand and live rocks on my aquarium turn brown?
by Aquaboy on Sunday, February 21st, 2010 | 3 Comments
i have a 90g saltwater tank and the sand and the live rock are turning brown.. i have a smaller saltwater tank of 30g but i dont recall the sand turning brown? anyone help what can i use to remove this?
It’s just the bacteria that you got. It multiplies fast but don’t worry, it’ll fade out within a couple months at most.
If your sand is truly turning brown-brown, a sort of rusty to chocolate color, this is diatoms (just a discoloration).
If your sand is turning brown-brown with an almost slimy, filamentous quality to it, this is dinoflagellates (picture stringy, tan to brown snot).
Both of these are protists which thrive in nutrient rich water, particularly that of tanks in dire need of a water change or those which are cycling. Keep up with your water changes and make sure to keep your nitrates as low as possible. You can also easily combat dinoflagellates by buffering your take to maintain a pH of 8.4 (which, really, is an ideal pH for saltwater anyway).
If your “brown” is more of a reddish to burgundy color, in slimy, almost filamentous patches occasionally sprouting bubbling to them, however, this is the dreaded cyanobacteria. Although cyanobacteria is generally referred to as blue-green algae, it often presents in saltwater tanks as this classic burgundy color. Cyanobacteria is a true bacteria with algae like properties, meaning it is diabolically annoying to get and get rid of! There are products such as Chemiclean which will destroy cyano, but they can be a bit iffy to use with certain invertebrates and if you cannot absolutely guarantee that you can do your follow up water change within 24 to 48 hours. To combat cyano bacteria, make sure to cut back on light (8 to 12 hours per day total), nutrients (keep up with your water changes and regularly clean the collection cup/well on your skimmer) and phosphates (use ROdI water as a base for mixing your water, use PhosGaurd or another GFO in your filter, and feed only foods that are low in phosphates). Cyano also tends to proliferate in areas will less flow, so you may simply need to reposition or change the angle on your powerheads to keep the water moving.
G’luck!
if your tank is still cycling that is normal to happen. and after your tank is done cycling the brown will be gone. if your tank is already cycled and you are having brown on your sand and rocks it is a sign that wither your nitrates are high or your phosphate our high. i struggle so much with my nitrates in my tank and i always have brown algae on my rocks and sand. my nitrates in my tank are 20ppm. what you can do is get your water quality perfect or close to perfect. also it could be a sign that either your light are too strong or you are leaving your light on in your tank for too long. since you are having algae problems in your tank you should leave lights off for a couple of days and you will see no more brown algae on your rocks and sand. but that only fixes your problem temporarily it is good to fix the problem from the source. but if you have corals i wouldn’t recommend for you to leave light off for that long in your tank. i keep my light on 8 hours a day since i have corals in my tank. also make sure you are using ro/di for you water changes and top off. tap water is a big no no for saltwater tanks. lots and lots of phosphates and nitrates in tap water. also buy some snails and crabs too they should take some of that brown algae of your rocks and sand