Where are my phosphates coming from?

[neurotik]

I have a 55 gallon planted tank, dosing dry ferts using EI, pressurized CO2, 2.3wpg of lighting. I have been testing my phosphate levels the past couple of weeks, and after each 50% water change my levels are just under 1.0ppm, but as the week goes on, even without dosing any phosphate this week, my levels have risen to nearly 2.0ppm as of this evening. What could be causing me to get such high phosphate readings even when I am not dosing any, and is this a bad thing? It hasn't ever went above 2.0ppm by the end of the week, but I'd like to try and keep it closer to 1.0ppm by the end of the week if possible.

I have tested my tap water several times and I see no traces (or extremely minimal traces) of phosphates in it, so I'm not sure where else I would be getting it from. Any suggestions or ideas?

 

[thominil]

Are you feeding anything freeze-dried?

 

[neurotik]

Are you feeding anything freeze-dried?

I feed my fish some freeze-dried blood worms a couple of times per week as a little treat, that's it though. The rest is just TetraMin crisps and Hikari Carnivore Pellets.

 

[thominil]

That may be where it is coming from in combination with something else.

 

[neurotik]

Interesting. I'll stop feeding the blood worms for the rest of the week and see what happens. Any idea what the "something else" could be?

 

[thominil]

Nope, there may be something else, or it could just be the bloodworms.

 

[neurotik]

Weird. Well, I'll stop feeding the blood worms for the rest of this week and also won't be dosing PO4 this week and see where my levels are on Sunday before I do my PWC. If I'm currently getting a reading of about 2.0ppm, any idea how much of it should be consumed by the plants between now and Sunday so I'll know what to expect when I check my water this weekend. If it's actually being caused by the blood worms and nothing else, should I expect to see my levels drop to 1.5ppm, 1.0ppm, lower/higher?

 

[HN1]

That depends on what types and how many plants you have. I'm not sure anyone can give you an estimated value.

 

[neurotik]

I have a bunch of Wisteria, Cabomba, a little bit of Anacharis left over from before I upgraded my lighting and started getting more serious about planting my tank, and some Anubias, if that helps at all with making an estimation.

If anyone else happens to come up with any other ideas of things that could be raising my PO4 so high, please let me know throughout the week, as I'm very curious as to what is causing it.

 

[HN1]

Those plants don't tend to be nutrient hogs so I wouldn't count on them to take care of any Phosphate or nitrate.

 

[neurotik]

So should I even be dosing either of those nutrients each week then if those plants aren't going to be using many of them?

 

[Purrbox]

Food, rocks, gravel are the most likely culprits if it's not coming from the tap water.

 

[neurotik]

Are there certain types of gravel that would cause it, or just all gravel in general? And as far as food goes, is it just freeze-dried foods, or is it any food and/or the amount of food being fed each day as well? I don't have any real rocks in the tank, just an artificial cave structure.

 

[neurotik]

So this is totally starting to bother me now. I have not fed any freeze-dried foods between yesterday and today and I have not dosed any phosphates into my water. I just did a water test and I'm now getting readings of somewhere between 3.0 and 4.0 ppm. What the heck could be causing this to happen all of the sudden? I have not added any new rocks, gravel, or decorations to my tank that would be adding phosphates in to my water.

 

[hacket]

Check out this site: Algone.com - Phosphate in the Aquarium
It seems pretty informative. According to that site, any fish food can cause a buildup of phosphates.

 

[neurotik]

I was actually reading that site earlier this evening when I made my previous post. I'm very careful when I feed my fish each morning so that I do not over feed them, and for my PO4 to increase literally in one day from barely 2.0 ppm to nearly 4.0 ppm really concerns me, especially since I specifically fed my fish next to nothing this morning just to be sure I wouldn't throw off my water test later this evening. I'm going to do some extra cleaning of my gravel this weekend when I do my 50% water change. Going to try and vacuum all of the gravel pretty deeply, trying to get underneath all of my plants in the back and stuff to clean up any rotting plant debris that may be laying down in there that could be releasing extra PO4.

If anyone else has any suggestions or experiences with this happening in the meantime, please let me know

 

[HN1]

Actually Hacket's link was good for another reason. I've used the Algone product in my SW tank and had terrific results. I normally wouldn't recommend any filer media solution, but it just about wiped out my bad cyano and HA issues. Might be worth a try while you get to the bottom of it.

 

[neurotik]

I'll consider trying some of it. I'm surprisingly not experiencing any new additions of algae in my tank since I went to pressurized CO2, even with the increasingly high levels of PO4, which is good I suppose. So I'm not sure if these higher levels are a 'bad' thing right now, but I'd still like to know where they are coming from at the very least.

 

[HN1]

Gotcha. I'd say that if you aren't experiencing algae issues and have good plant growth to leave it alone. I do understand (and commend) the need to understand why though.

 

[neurotik]

Definitely have good plant growth, and I suppose it has its benefits of not having to dose PO4 in my tank each week until I figure out what the heck is going on, haha. Will these higher levels of PO4 have any negative effects on my fish or anything?