Algae Hypothesis...

[scubasteve]

I have this problem with algae in my tank, mainly a green algae that grows on the rocks and a green/brown slimy sheet algae that grows on the glass. I have been using RO/DI water for around 8 months now and the algae is still there. My tank always has higher nitrate levels also(don't know an exact number off the top of my head but I know its on the upper end). I feed my fish formula frozen cubes for dwarf angels usually by just breaking them in two and putting them in the water every other day...I was reading some posts about liquid that is in the frozen food that can cause high phosphates.

My three questions are, do you think my feeding habits could be contributing to some of the algae growth?
and..
Are the high nitrates a result of the algae growth?(my nitrite and ammonia are zero)

Any ideas on what I can change or adjust to lower the amount of algae?

 

[rubikcube]

The frozen foods supposedly contain a lot of phosphates. I usually thaw a cube in RO water, then rinse it in RO water. To get rid of the last few stubborn phosphates, I use phosguard. That is pretty much taking care of the hair algae.

From what I understand, any phosphate is too much and will cause algae problems.

 

[Brenden]

I would try a different type of food. preferably frozen and see if you notice a change.

Are the high nitrates a result of the algae growth?

Just the opposite. Algae growth is a result of the high nitrates. Have you checked your phosphate level?

Any ideas on what I can change or adjust to lower the amount of algae?

Type of food and how much you feed. Run some type of nutrient removal media in you filter like poly filters, PURA filters, phosguard etc. Also regular WC will lower the nutrient level. In the 8 months you have been using RO have you checked water or replaced filters? Something is feeding the algae, once you remove the source it will disappear.

 

[melosu58]

Totally agree Stop the source. Do you have a skimmer. This will help take DOC out of the water that end up as the fuel source

 

[scubasteve]

Here's some readings I got tonight, I don't have a phosphate test kit, which I realize would be applicable here but that will have to wait till I get to the fish store.
ph: 8.1
alk: 2.5 Meq/L
ammonia: 0 mg/L
nitrite: 0 mg/L
nitrate: 80 mg/L

To me it seems like all my levels are close to normal with the exception that I knew, nitrate. Would food and junk stuck in a filter pad cause the nitrate levels to rise?

 

[Brenden]

Would food and junk stuck in a filter pad cause the nitrate levels to rise?

Yes

 

[dorian965]

old lights may contribute also.

 

[ccCapt]

How often and how big are your water changes. 80 is extremely high...

 

[scubasteve]

I usually do 5 gallons which is ~7% every 2 weeks is that too small? Should I up it to 10?
I'll admit I've been slacking off cleaning the canister filter and theres probably alot of gunk stuck in the filter pads, this weekend I'm going to put fresh filter media in and clean the hoses out. I've been doing 5 gallon water changes this week like every other day so come this saturday I would have changed out 15-20 gallons of water, we'll see if that makes any difference.

If i understand this correctly, although nitrate isn't immediately harmful to the fish like ammonia and nitrite, it can have an effect long term? correct?

 

[melosu58]

I would definitely do more

 

[seaham358]

You need to test the water for PO4 before you go over board with water changes. Your ro/di may contain PO4 and or Nitrates. When DI units get old it will pass by them. So doing wc with water that has them is just feeding the algae.
Also if you have high NO3 and PO4 in your tap water 1 di may not be enough. I run a dual DI because of my water at certain times of the year has high po4.
more info on the tank would be helpful also...
size, substraight, sump, w/d and so on...

good luck with the battle..

 

[scubasteve]

Hey,
I didn't even think of checking the NO3 in the newly ro/di 'd water , I will check it tonight because I just made a new batch of water last night.

Specs on the tank:
72gallon bow front, ~60lbs of regular rock for about a year now, crushed coral substrate, Fluval 404 filter, 3x Maxijet 1200's , lights are on for 7 - 8 hours a day, , no sump no fuge.

Fish: 1 bicolor dwarf angel, three green/blue chromis.

i realize that crushed coral substrate might be a place for stuff to be trapped under,even though it is pretty finely crushed but I was thinking of swapping it out for sand down the road , just need some money.

I did a good algae scraping last night and made it spotless, algae free. I said this in another post, but i'll admit that I haven't really kept up with the tank lately and have been busy with other stuff but i'm ready to get back in it. So in that time alot of junk could have built up in the filter and substrate, i've been trying to vaccum stuff out pretty well though.

 

[cmor1701d]

crushed coral substrate, Fluval 404 filter

= High Nitrate

The CC is trapping detritus and so is the cannister filter. You need to up your water changes to around 10% weekly along with good vacuum maintenance of the CC substrate and weekly cleaning of the cannister filters. That should help get the NO3 down.

Also, what brand test kit are your using?
I find the SeaChem readings to be very high while the Salifert gives me very low readings.