Thoughts of Carbon leeching Phosphates

[Proplanter]

After reading that sometimes carbon filters will leak phosphates, I was thinking about my past tanks. I've always used those pads that have the activated carbon in them, pretty much unremovable unless you go through lots of trouble. I was wondering why my tanks usually flourish early on and I came to the conclusion that possibly the carbon might have been leeching phosphates into the water that my plants may not be getting. I generally use FloraPride, which as far as I know does not provide phosphates. I never change my filter pads, I just rinse them so..

Eventually my tanks would slow down in growth or almost stop in growth, and occasionally they would even "melt".

Could this be the symptom of a phosphate deficiency in my aquariums?

I even ran off to my local pet store today to look for a good fertilizer, of course they didn't have any at all  , other then a leaking bottle of FloraPride, about to go off and try another store in the area to look for something that provides adequate nutrients..

Anyone have any thoughts on this? or can you recommend any sort of "all in one fertilizer" or a combination that provides most of the nutrients needed for healthy plant growth?

Regards,
Will

[SerVo]

First you'll need a test to test for how much phosphate is already in your tank (and how much you add).

Carbon has a funny way of absorbing everything at first, then as it becomes saturated; it likes to give up harder to hold chemicals for easier ones.  I've seen this happen at events like a water change, when the carbon to water equilibrium is interrupted.

Replacing carbon often will help prevent this leaching, but at the same time will also absorb more phosphates that you add.

In reality I don't run carbon unless I see a reason to; the water starts to get funky, I need to remove some meds, etc.

Also if you use carbon, make sure you also keep some kind of biological filtration in your tank, IE a sponge.  Bacteria will populate on carbon, and if you remove it.... it will have to regrow back. 

As for the ferts themselves: I like flourish stuff.  They come in a couple of varieties so you can dose what you want.

[Carr]

Plants have a reserve of nutrients that they build up during 'good' times that they can draw on when in a deficiency. Likely what happened was that the plants were relatively deficient from the time you put them in the tank, and it just took that long for them to use up whatever nutrients they had in store and then to show signs of deficiency. In order to cover all your bases, you need to dose NitrAte, phosphate, potassium, iron, and a trace mix. I get the raw powders and dose them individually, $20 is good for a year or more so it's a cheap route that takes care of everything. I've been running into some sudden deficiency problems out of the blue lately, that started around the time when I started using carbon, so I think carbon can also remove stuff that the plants need. I won't be trying it again in my planted tanks.

[Proplanter]

According to http://www.csd.net/~cgadd/aqua/art_plant_nutrient.htm , I'm almost certain is must be phosphorus that I'm missing. I don't want to get to complicated into the testing of my water, at the moment anyway, I usually try to approach things simply. I went ahead and ordered some small bottles of Flourish (NPK, trace,iron, and the original, not expensive at all really), I'm hoping to see some improvement. The picture of my Anubias Nana in this thread: http://www.petfish.net/forum/index.php/topic,69526.0.html It seems like its showing text books signs of P deficiency, although it seems to have some sort of algae on it

I guess I'll have to do some experiments and figure out my water slowly, or else go out and get the test kits for this stuff (as far as I know phosphate is pretty cheap, I saw it in the store for like $7 bucks, I hitting myself in the head as to why I didn't buy it. I was so focused on finding some sort of good fertilizer, I didn't even really look at the other stuff.

I've read that phosphorus generally comes from fish waste (?), in this case I only have 3 fish in my 55g (pleco, and 2 angelfish) and tons of plants. Possibly the tank having so few inhabitants and so many plants is the main cause of the issue. I don't know, I'm just guessing here . I just know my plants are not growing like they used to and I want to fix it.

As a matter of fact, I've barely have any sort of algae growth (other then the fit of green water a little while back, who knows). So I doubt I have many excess nutrients that are causing issues.

My mind is boggled  .

[Proplanter]

UPDATE: I think I was on to something with the carbon, not so much it leaching phosphates, but it removing something  .

As an experiment for my little 10g plant tank, I started to run water that I took from my 55g though a carbon filter in a bucket about a day before I planned to add it to the tank ( I don't really know how long it takes carbon to work  ). It been a little over a week, and the growth of the plant in there has taken off    .

What could carbon possibly be doing for my plants? can there be something in the water that inhibits plant growth ( but is perfectly fine for fish? since I have no problems with them)?

I'll probably start doing this for my 55 since it worked so well, that will be the real test I suppose.

[Carr]

Some carbons do leach phosphates, so I would guess that this is the case. Especially fresh carbon.

[Essabee]

Between planting and the plants growing there is always a waiting period for the plants to set to the conditions of the tank. This has nothing to do with the carbon.