How much do you feed a reef tank?

LordJoshaeus · Mar 31, 2020

Hi everyone! I figured out the likely reason why my prior marine tanks failed...overfeeding. My 10 gallon marine tank, for example, was getting 1/4th tsp flake food most days, and when I alternated that with frozen food it got a quarter of a cube...I didn't realize that at the time, but that is FAR too much food for any ten gallon, much less a reef tank, doubtless causing my endless algae problems that eventually caused me to leave the marine hobby. My question is, how much should one feed a typical reef tank? For comparison, I am now feeding my three freshwater tanks (with a betta smaragdina in two of them, and a small persian killifish colony in another) only .15 ml TOTAL mini omega one pellets or mini bug bites each day, and most of that .15 ml goes to the killies. Thanks

Chefwheredyougo · Mar 31, 2020

Only what the fish will eat in a couple minutes. Some fish need to eat multiple times per day.
I spot feed my coral every other or every 4th day.

LordJoshaeus · Mar 31, 2020

Chefwheredyougo said:
Only what the fish will eat in a couple minutes. Some fish need to eat multiple times per day.
I spot feed my coral every other or every 4th day.

OK. On a related note, how do you divide a frozen cube into smaller portions? Should I thaw it, divide the food and liquid into smaller portions, refreeze it, and thaw out each portion as it is needed?

Malifry97 · Mar 31, 2020

A 1/4 of fish food is definitely not too much for a ten gallon with proper nutrient export. I do a 30% WC each week and have no filter, skimmer or fuge and I feed a half cube. My tanks levels are stabilized at 5-10 nitrate and proper phosphate. I plan on getting a fuge eventually but this build has started out as a low tech budget build.

LordJoshaeus · Mar 31, 2020

Malifry97 said:
A 1/4 of fish food is definitely not too much for a ten gallon with proper nutrient export. I do a 30% WC each week and have no filter, skimmer or fuge and I feed a half cube. My tanks levels are stabilized at 5-10 nitrate and proper phosphate. I plan on getting a fuge eventually but this build has started out as a low tech budget build.

Oh boy...now I'm not sure why the tanks all got algae infested. My 10 gallon had similar nitrate levels to yours and LOTS of macroalgae...plus 40% weekly WC's.

NexisG · Mar 31, 2020

LordJoshaeus said:
Oh boy...now I'm not sure why the tanks all got algae infested. My 10 gallon had similar nitrate levels to yours and LOTS of macroalgae...plus 40% weekly WC's.

Did you use tap water for water changes and top off or RODI. Some people can get away with tap but others have stuff In their water that creates crazy algae growth.

LordJoshaeus · Mar 31, 2020

NexisG said:
Did you use tap water for water changes and top off or RODI. Some people can get away with tap but others have stuff In their water that creates crazy algae growth.

Distilled water for both top offs ad water changes. Good question, though.

Hemmdog · Mar 31, 2020

Roughly 1 square inch of frozen food per 30 gallons 3x a day.

LordJoshaeus · Mar 31, 2020

Hemmdog said:
Roughly 1 square inch of frozen food per 30 gallons 3x a day.

Square inch? Or cubic inch?

Malifry97 · Mar 31, 2020

LordJoshaeus said:
Oh boy...now I'm not sure why the tanks all got algae infested. My 10 gallon had similar nitrate levels to yours and LOTS of macroalgae...plus 40% weekly WC's.

Strange, did you use RODI or tap water

fish farmer · Mar 31, 2020

I really think it all depends on the biomass of the tank as well. You could have very well been overfeeding if things weren't in your tank eating the extra food.

I have three fish in a 29, two clowns and a sixline and I'm usually feeding 1/2 cube of food one day and maybe 1/8 tsp of pellets on other days. I shave off food from a frozen cube.

Hemmdog · Mar 31, 2020

LordJoshaeus said:
Square inch? Or cubic inch?

Cubic inch, like pe mysis cube size, hakari are bigger, I’d do a half cube of hakari per 30 gals 2x-3x daily.

LordJoshaeus · Mar 31, 2020

Malifry97 said:
Strange, did you use RODI or tap water

Distilled

Rmckoy · Mar 31, 2020

LordJoshaeus said:
Distilled water for both top offs ad water changes. Good question, though.

Even though it’s advertised as distilled . a tds metre is the only rest way to tell .....
any dissolved solids can contribute to excess nutrients .

being only 10 gal nitrates would accumulate and colonize quick .

LordJoshaeus · Mar 31, 2020

Rmckoy said:
Even though it’s advertised as distilled . a tds metre is the only rest way to tell .....
any dissolved solids can contribute to excess nutrients .

being only 10 gal nitrates would accumulate and colonize quick .

Nitrates were seldom higher than 5 ppm...the only time I remember them being higher was after the 10 gallon's first occupant (a banggai cardinalfish) died, when it briefly spiked to 15 ppm. Don't recall the TDS on the distilled water...I was testing it, I just don't recall the exact numbers.

Hemmdog · Mar 31, 2020

LordJoshaeus said:
Nitrates were seldom higher than 5 ppm...the only time I remember them being higher was after the 10 gallon's first occupant (a banggai cardinalfish) died, when it briefly spiked to 15 ppm. Don't recall the TDS on the distilled water...I was testing it, I just don't recall the exact numbers.

That wasn’t your issue then. Nitrate should be 5-25ppm What was your phosphate? That’s more likely to contribute to algae growth anyways. Flake food is loaded with phosphate, that’s why I never feed pellet/flake food.

LordJoshaeus · Mar 31, 2020

Hemmdog said:
That wasn’t your issue then. Nitrate should be 5-25ppm What was your phosphate? That’s more likely to contribute to algae growth anyways. Flake food is loaded with phosphate, that’s why I never feed pellet/flake food.

Ah...ok. I don't recall phosphate values ever being especially high either, but next time I attempt to keep a marine tank I will limit the dry foods. It's ironic...excess nutrients cause algae problems in marine tanks, freshwater tanks typically get algae problems when nutrients (frequently CO2) are in short supply (I'm experimenting with high tech tanks right now).

Mrod · Mar 31, 2020

Sometimes light can also contribute to too much algae if run too strong, too long, natural sunlight, etc.

If food great advice above

LordJoshaeus · Mar 31, 2020

Mrod said:
Sometimes light can also contribute to too much algae if run too strong, too long, natural sunlight, etc.

If food great advice above

Ah...this could have been the issue. The light was advertised to supply 100 PAR under 20 inches of water...and this was a 10 gallon. How much PAR is good for most marine tanks? I like macroalgae a lot but would likely keep some corals, chiefly LPS and softies.

DHill6 · Mar 31, 2020

LordJoshaeus said:
OK. On a related note, how do you divide a frozen cube into smaller portions? Should I thaw it, divide the food and liquid into smaller portions, refreeze it, and thaw out each portion as it is needed?

I freeze the flat pack, break off a piece and cut it into small pieces. Then place the pieces into a small container , place back in freezer. Easy to pull out a piece or two.