# Understocking a problem with NPT?



## CoryWM (Mar 26, 2008)

I have a 55g NPT that is newly setup with 6 celestial pearl danios. What I am wondering is, Will the soil supply enough nutrients, and co2? Until my fish start breeding? Also should I overfeed the tank to supply nutrients? As I once read a quote that Diana, feeds the tank, not the fish. meaning regardless of fish load, it got the same amount of food.'

I am currently Trying to acquire more CPDs.
Thanks,
Cory


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## davemonkey (Mar 29, 2008)

In my experience, you'll find yourself short on nutrients with a light fish-load in NPT unless you "overfeed". Diana's advice will serve you well. "...Feed then tank..."

Something else you can do if you are wary of overfeeding, use a light amount of ferts until you get your fish population up. Liquid ferts are good for this.


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## HeyPK (Jan 23, 2004)

Fish food is good for nitrogen and phosphorus, but it is rather low in potassium. If you grow a lot of plants, potassium deficiency can develop in a natural planted tank.


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## Michael (Jul 20, 2010)

If my memory of a recent reading of Walstad's book is correct, she estimates that the soil layer should provide enough nutrients for the tank for 1 to 2 years. This assumes lots of plants, and relatively low stocking rates for fish. During that period, fish wastes, excess food, and other organics build up in the substrate and "take over" as the soil nutrients are depleted.

Waldstad believes that good quality fish food contains all the essential nutrients for plants. I have read that one aquarist who has concerned about potassium always fed some spurulina(spelling?) food because it was high in this nutrient. Most foods for algae eating fish have this ingredient.

Low fish population is also a good argument for snails. They breed rapidly, consume the excess fish food, and their feces enrich the substrate.


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## davemonkey (Mar 29, 2008)

The soil will provide sufficient micros and carbon, but only so much macros. That's why you have to depend on fish food and waste. It may depend on the soil you start with, but I've had potassium and nitrogen defficiencies in all 3 of my NPT's that I had to correct with exrta food and added potassium fertilizer.


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## mudboots (Jun 24, 2009)

I agree on using snails to help make up the difference if you want to make sure excess food is getting utilized and not potentially subject ot decay by fungus. Not that fungus is going to create tremendous problems, but it is quite unsightly. 

Re the potassium, I feed algae wafers made of spirulina but also toss in the occassional "dash" of potassium in my 125. In the picotope I feed the algae wafers to the fish and do not add anything else, but I had some slow release fertz mixed with the soil when the tank used to be emmersed, so that is giving quite a bit of nutrient load.


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## CoryWM (Mar 26, 2008)

The only reason my stocking level is so low, cause the more I read, the more things I find that prey on the CPD eggs, including the parents. I could add snails, or shrimp, or endlers, etc. I'm just hoping to have just CPDs and a big breeding colony at that 

ANyone have any experience with the CPDs?


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## Michael (Jul 20, 2010)

Cory, I can't help you with the CPDs.

Mudboots, you are probably the aquarist I was thinking of re potassium and spirulina (thanks also for correcting my spelling).

What are the symptoms of nitrogen and potassium defficiency we should watch for?

--Michael


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## CoryWM (Mar 26, 2008)

Just from memory, I think potassium is holes in the leaves. and Nitrogen is yellowing of tips and consuming itself?


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## mudboots (Jun 24, 2009)

CoryWM said:


> Just from memory, I think potassium is holes in the leaves. and Nitrogen is yellowing of tips and consuming itself?


I think that's about right.


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