Question about tannins in feed and C02

[Cecil]

My tank water is taking on a brownish tint. It's not iron as I'm removing the iron in my make up water before I add it. I've read this could be the tannins in the feed? Is this a possibility? Anyone else see this? The only other thing it could be is a brown aglae bloom, which I've had in one of my outdoor ponds, but I have doubts.

Thoughts?

Also will my 335 gallon system with about 25 lbs. of fish in it produce enough C02 to produce drowsiness if I spend a lot of time in that area? It's in my basement and I do work down a short hallway not far from the system. Seems i get sleepy down there but maybe it's my imagination or I just dont' want to work. LOL

No plants in the system btw.

[Crusty]

Hi Cecil, yes some of the brown will be coming from tannins in the feed (phenolic compounds in plants used as binders and protein source) and some will be from humic acid created by the action of heterotrophic bacteria breaking down the organics in your system. Plants will do a reasonable job of removing most of it.

Can't say if the co2 is at high enough levels, but if you have no ventilation in the basement, there is a fairly good chance it is preventing you from working (great excuse for the boss!). Keep in mind 1kg of feed can produce 1.3kg of co2..

[kellenw]

Hiya Cecil,
Aquamax feed really stains the water in my experience. Plants help a little bit, but usually it's not an issue to fish health, just "ugly". I'm assuming this is in your BG tank. How are they doing? Condello sized yet? :)

[Cecil]

Hiya Cecil,
Aquamax feed really stains the water in my experience. Plants help a little bit, but usually it's not an issue to fish health, just "ugly". I'm assuming this is in your BG tank. How are they doing? Condello sized yet? :)

They are now 4 to 6 inches. (late July 2010) Started out in February as about 1/2 to 3/4 inches.

If I did want to remove the tannin stain of the water what kind of filtration would be needed? I know it's just ugly but...

[kellenw]

Cecil -
I would think you'd need to use a very fine micron filter/polisher. I wonder if it could be efficiently settled out or separated chemically with something safe. I'll have to look into that.

By the way, REALLY enjoyed the article about your system in PondBoss Magazine. You're bringing RAS to a whole new crowd with that. Very cool! :)

Also, fantastic growth with the BG!

[GaryD]

Hi,

While some of the "tannin" discolouration in fish tank water may be because of food, I've heard Crusty say that it's also evidence of dead bacteria in the water.

If it bothers you, change some water out and use it to water your non-AP shrubs and trees.

Gary

[Cecil]

Hi,

While some of the "tannin" discolouration in fish tank water may be because of food, I've heard Crusty say that it's also evidence of dead bacteria in the water.

If it bothers you, change some water out and use it to water your non-AP shrubs and trees.

Gary

Gary,

I actually do a lot of changing out of water, probaby more than I need to. Interesting -- dead bacteria...

[bigdaddy]

Hi Cecil,I know you are much more experienced than me

But have you thought about incorporating lump or natural charcoal,I'm using it in my new trout system and intend to use it in different grow beds as I expand,I have not got any substantial personal results from it yet but I can think of two APHQ members who use it in their systems and they swear by it.Obviously the systems are not on the scale of yours but it may be a thought for you.

Cheers.

[Crusty]

They are now 4 to 6 inches. (late July 2010) Started out in February as about 1/2 to 3/4 inches.

If I did want to remove the tannin stain of the water what kind of filtration would be needed? I know it's just ugly but...

GAC (Granulated activated carbon). As long as the water is actually clear it will be fine and I would not bother removing it.


Hi,

While some of the "tannin" discolouration in fish tank water may be because of food, I've heard Crusty say that it's also evidence of dead bacteria in the water.
The tannins are caused as I said above. The dead bacteria make up a majority of the solids <20micron in a recirc system.

[Cecil]

Thanks Crusty!