Rising Nitrates & Phosphates

[PrettyFishies]

I did my bi-weekly tests on Sunday and got a reading of just over 17ppm for nitrate and about 1ppm for phosphate. I added enogh gregwatson potassium nitrate to add 3ppm. I added no phosphate.

Wed's test: 37ppm nitrate and ~2ppm phosphates

Tank setup:

20gal
65w 6700k colormax (11 hrs)
pressurized Co2 - target 30ppm (kh3.5/PH 6.5)
Heavily Planted
Dose w/ Flourish and GW potassium 3x a week, Iron 1x a week

[Purrbox]

In evaluating your results we need to know the test kits that you're using and whether or not you've calibrated them.

It's also good to keep in mind that Nitrates and Phosphates also come from fish waste. Further not all of the measured Nitrates and Phosphates are necessarily in a form usable by the plants.

[PrettyFishies]

My nitrate kit is a LaMotte, Phosphates by Seachem (although, they were in the garage over the winter, so I'm not sure - even so, it raised from Sunday)

[Purrbox]

These are good kits, but if you're going to be basing your dosing on them they really should be calibrated.

I suspect that the real reason is that you're feeding your fish faster than your plants are growing and/or there's a nutrient shortage preventing the uptake of other nutrients.

[PrettyFishies]

Originally Posted by Purrbox

These are good kits, but if you're going to be basing your dosing on them they really should be calibrated.

I suspect that the real reason is that you're feeding your fish faster than your plants are growing and/or there's a nutrient shortage preventing the uptake of other nutrients.

Please elaborate on both statements... thx

(I DO have a LOT of fish do to two over-zealous swordtails)

[Purrbox]

To calibrate your test kits you need to test them against a range of reference solutions. This ensures that 1. Your test kits are accurate for a range of values and not only accurate at one value or off on all values and 2. That if your test kits are off you can adjust the results based on know variances to ensure that you are dealing with good numbers. Even the good test kits can't be 100% trusted to be accurate unless you check them. They're just more likely to be accurate or close to accurate. Since you are dosing to specific values, then you need to make sure that you are dealing with good numbers.

If you have a lot of fish that you are feeding heavily and your plants aren't growing fast enough to keep up, then your Nitrates and Phosphates with rise as a result. The issue is to determine whether you need to feed your fish less, determine why your plants aren't keeping up, or accept that your fish to plant ratio is such that you don't need to dose Nitrates and/or Phosphates.

Now if you're short on another nutrient like Potassium, then it will be harder for the plants to use up the other nutrients like Nitrates and Phosphates. If the plants can't use them as efficiently then quite often you'll start to see the nutrients which are in sufficient supply start to rise. Remedying the deficiency will allow the plants to start using the other nutrients and stop or reverse the climbing levels.

Hope that helps.

[PrettyFishies]

It does... thx... I dose potassium, 15ppm Sunday after the PWC, Tues and Fri...along with my flourish. I'm okay with not having to dose the phosphate and nitrate. Does it seem like I need to up the dosage of Potassium?

[Purrbox]

Are you seeing any signs of Potassium deficiency? ie Pinholes in leaves that slowly expand. If so then you may need to up your dosing. Potassium was just the example, and another nutrient could be the real culprit.

[Plantbrain]

Has your plants slowed their growth rates?
Has there been any algae etc?

Try adding a bit more CO2 and watch that if the routine you have been doing all along has not been changes. A good cleaning, filter, vacuuming the sections where you uproot/trim etc might help a fair amount also.

Regards,
Tom Barr

[PrettyFishies]

I've seen pinholes in my Anubias nana, but not in any others.

Plants seem to be growing at the same rate.

I'm currently experiencing a growth in algae - Black fuzzy stuff that sits on the DW, but not the plants and green algae on DW, plus hair algae on Vals.

I only noticed the green and hair algae after introducing the new 6700K Colormax bulb.

As for Co2, I'm already at 33 ppm with a controller. Plants are also pearling...

[PrettyFishies]

bump

[rich311k]

I got hair algae after changing out my bulbs as well. I guess the higher light from the new bulbs threw things out of whack. I increased dosing slightly removed the algae manually and it has not come back.

I get BBA on my wood too. No where else. My drop checker is nice and green so I didn't want to pump up the CO2 any further. I decided to just cover the whole wood in moss. So far the moss is winning and I cant see the BBA any more. I can live with the little that pops up now and then. A squirt of excel usually takes care of it.

[PrettyFishies]

Thanks...

Well, for today's dosing I put in 25ppm instead of 15ppm of Potassium.

I can only assume that my phosphates and nitrates are still elevated/ I plan to test before and after Sunday's PWC.

Moss may be a good idea... Java or Xmas?

[rich311k]

I have xmas. I hope that was 25 and not 225.

[Hoovercat]

I would up the CO2 a bit though you CALCULATE 33ppm. You're still using that CO2/pH/KH chart. I tell you the darn thing LIES. I also think you need to throw out that PO4 kit as they ALL lie. Dose a bit more PO4 to make sure there's some there.

I asked on another thread about your photoperiod because manipulating it will help you regain control as well. Right now it might even be a good idea to turn the lights off for a couple days to "reset" the tank. Do a big water change before and after the lights out and restart EI at lights on. When you start back, try 6hrs. of light per day and work up to no more than 8-10.