# Phosphate Deficiency?



## Dr.Awkward (Jun 6, 2010)

Hello. I have a 5 gallon NPT that I think has a phosphate deficiency. I am looking for recommendations on the best ways to put phosphate back in the tank without actually dosing ferts. I'd like to know whether I need to tear down this tank and set it up again or if there is a way to sneak in something that releases phosphates without disturbing everything too much.

For plants tank has Hygrophila lacustris, Bacopa caroliniana, Vallisneria americana and frogbit. I have a 13 watt CFL bulb over the tank and a very small internal filter for water movement. The light is on a timer to turn on for six hours, turn off for four hours and turn back on for six more hours. The tank does not have access to natural light. Substrate is just under an inch of organic potting soil, a few handfuls of oyster grit and crushed coral and about an inch of 2mm red flint sand.

There are about a dozen Heterandria formosa and a few ramshorn snails. The tank has been set up for five months. There are no traces of ammonia or nitrite, nitrate is around 10-15ppm, phosphate is 0ppm, pH is 8, KH is 4 degrees.

The hygro and bacopa both grow fast and I prune them regularly to keep them compact enough for the tank. The bacopa usually has some emergent growth. I remove frogbit almost daily to make sure enough light reaches the bottom of the tank.

My problems are with the vals and green spot algae. The vals spread quickly but the plants only grow to be 3-4 inches tall. Over the past couple months I've started getting green spot algae on the glass but not on any leaves. I have not noticed any signs of deficiency on the leaves, just the stunted growth on the vals. A few weeks after I set up the tank I noticed signs of potassium deficiency on some leaves so I started throwing in about half a dozen spirulina sticks every other day. That seemed to remedy the problem.

I thought the oyster grit and crushed coral in the substrate along with the phosphate in my tap water from farm runoff would be enough, but I don't think it is. I have started pouring water I use to thaw frozen food like bloodworms and brine shrimp into this tank in an effort to increase the phosphate. I have also started doing 20% water changes every two weeks in addition to adding about a gallon a week replace water lost from evaporation.

I have another NPT that does not have any problems. It is bigger with lower lighting and only holds crypts and a couple killifish.

Here is a picture of the problem tank I took about a month ago. Since then the vals have multiplied but not grown any taller.



Thank you reading this and for any suggestions you can throw my way.


----------



## davemonkey (Mar 29, 2008)

Phosphates can be found in prepared fish foods (flakes or pellets or granules). If you don't want to over feed and take a chance at over-doing ammonia, however, it may be wise in this case to buy some phosphorus fertilzer and dose it occassionally. Or perhaps add a couple fish and feed them some hefty portions of food.


----------



## Dr.Awkward (Jun 6, 2010)

Hmm, I'm already overfeeding for fertilizing purposes. Do you know if there a particular prepared food that has extra phosphate? I really don't want to dose fertilizer because I feel like that defeats the whole purpose of having a NPT.


----------



## HeyPK (Jan 23, 2004)

Since you have already tried increasing P by changing the water more often and by overfeeding, and that has not worked, there isn't much more to do other than dosing phosphorus directly in some form, such as KH2PO4. The symptoms of phosphorus deficiency are difficult to recognize. The plants are smaller and a bit darker. If they start growing faster and become larger after you add phosphorus, then you know your deficiency was, indeed, phosphorus.

If you just don't want to work with chemicals, you could try composting small pieces of dried liver in moist soil for two weeks and then extracting the soil with water, letting the water stand for about a week in a shallow pan, such as a Pyrex baking dish so that the mud can settle out and the solution can concentrate, and then pouring the solution in the tank. That will bring in quite a bit of nitrate as well as phosphate. That would be more 'natural', but quite a lot more work. 

Another way of doing it is to put about an inch of soil in the bottom of a plastic shoebox, cover it with about an inch of water, and then add some pieces of dried liver. Don't add too many, or you will get a bad smell. About 5 penny-sized pieces is enough. Let the liver decompose for four days, then lift it out with tweezers and place in the aquarium. One or two days later, add the water from the shoebox. Repeat. The soil provides a variety of bacteria which makes for faster decomposition and a smaller likelihood of a bad smell.


----------



## Diana K (Dec 20, 2007)

Just get some fertilizer tablets that have phosphate. There is nothing wrong with using fertilizer. A slow release product is easy to use, you do not have to add it daily and gives a long term solution. You can probably get a month or longer, especially with a low tech tank, on just one tablet in such a small tank.


----------

