brown algea/diatoms?

hi,a brown algea growth started 2 weeks ago on my 8 month old tank.its on rocks,sand,everything.i use h2ocean for salt,the ca in this brand is 450,my reading is about 520,does this have any bearing on the algea?lights on to long?
latest test results are---
ph=7.8-8.0
nitrate=0
nitrite=0
po4=0.5
amo=0
sg=1.024
from homework i have done on this and other sites says to go 3-4 days with lights off and to not feed.????
also?whats a good test kit for dkh and magnesium,,hard to find good ones here in regina,,lol

ty in advance

 

Unless you have added new equipment or sand it most likely not diatoms in an 8 month old tank.

Your phosphate should be 0.05 so I imagine your level is probably feeding what algae you do have.

What type of water are you using?
Cut back on feedings if you can.
Try some phosban or similar product for po4 reduction.

Also lastly an image of the offensive algae please. A macro shot if you can get it.

 

algea problm

i use only ro water.i tested the po4 with a nutrafin kit,the range on it is 0--5.0,i have only 0.5?that is supposed to be safe?i took some pics,,best i could do.

 

WOW, how did you get Diatoms in a 8 month old tank. You could do the light thing, but unless you fix the problem they will come right back. ABout the Phosphate readings, you can't get a good reading because the Algae is eating some of those numbers, so what you see is only slightly what you have. Diatoms will form also because of Silicates in the water.
It has been found that diatoms appear because of the presence in the water of silicates and silicic acid . To avoid having brown algae in the tank, all the hobbyist needs to do therefore is remove the silicate and the silicic acid both from the tank's water, and from the raw water used to prepare water for water changes, Kalkwasser, top-offs of evaporated water, and so on.
Note, as indicated, that it is not enough to treat only the aquarium. The raw water (e.g. tap, well, deionized, reverse osmosis) needs to be treated as well. If you do not, silicic acid will get into your tank's water and will, eventually, lead to the appearance of brown algae because the levels of silicate and silicic acid will slowly build up.

 

You might need to look into a DI to go with the RO or a GFO reactor.

Try testing the phosphates coming out of your plain tap water and compare to a fresh sample straight out of the RO unit and see if they compare. That is, if you are filtering this water from your tap through your RO unit. Probably post those findings on here so others may form an opinion on those numbers as well as I am sure others are more experienced in this than I am.

Sadly your reading is skewed because your bloom is eating up phosphates like mad so your readings are probably much higher than you are getting. That also means this can keep getting worse before it gets better unless you find the source of your phosphate.

Also, as Corailline said you can cut back on feedings or try phosban as well.

 

is it "jelly" or "snot" like? Kinda stringy or just powdery? Could be Dinoflagellates

 

I hope not dinoflagellates is the devil lol

 

its kind of powdery.i went to my lfs,i got a form of green sponge type filer media that is supposed to lower phosphates,and i bought some rowa phos,i put 3oz of rowa phos in the bag it comes with and placed that inbetween 2 layers of the green filter media ,put it into my hob filter.will test po4 in a few days to see if it dropped.with the po4 lower and silicates lower the alge should go away?so im told.lol
thanks to all who replied,,ill keep you posted...ty

 

Algae problems are usually caused by aquarium water with excess nutrients like phosphate, nitrates etc. You can try and siphon out what you can to remove the algae in the short term. In the long term you may have to examine how you care for your tank. There are some commercial dry foods also contain excess nutrients and other undesirable things like nitrates, phosphates etc so I strain/rinse my fresh/frozen foods before feeding my tank. You may want to consider feeding your fish less often. Also, changing your photo period, light bulbs more flow, using RO/DI water and a high quality salt with little if any NO3, phosphates etc like Tropic Marin may help too. Adding a phosphate remover and increasing flow in your tank may help too.