over the last 2 weeks, i noticed some algae grow, my plants stoped growing,some of the plant leafe tips melting (crypto)..., then i found that my nitrate is very high, 40-50 range, the po4 more than 2, i used lemotte kits and hagen, i have 140w light on 29G, I am using EI, CO2 TANK.
I stoped adding fert, did my 50% water change, 2 days after the NO3 up again and my po4, i waited one week, did another WC and same problem again.
i have 7 red nose tetra, 5 neon, 5 black neon, 3 oto. feeding the fish one time day.
my filter is eheim 2217.
what will drive my nitrate up? po4?
the tank is 8 month old, heavy plants

The algae isn't growing because of high nitrate or phosphate. It doesn't work that way. You have way too much light, to start with. You have almost 5 watts per gallon, where about 2 is all you need. If your lights are suspended above the tank a foot or so, that comment isn't correct, but if they are right at the top of the tank it is. How do you get the CO2 into the water, and how much do you maintain in the water? This actually looks to me like low CO2, with the plants being stunted by not having enough carbon to grow at the rate the lighting is driving them at.

If your "heavy plants" is anything like what I just had in my 45 gallon tank, the mass of greenery is also interfering with water circulation, which keeps the CO2 from reaching all of the plants. Do you use a powerhead in addition to the filter to better circulate the water?

I have my light bulbs 10cm high, and also had a similar amout of watts per gallon in my tank (96w/20g). I followed the recommendations of reducing the light and that helped dealing with algae (a 24w bulb was removed and now I work with 72w).

Another point is the quality of light, besides the quantity. You mentioned your tank is running for 8 months. Have you replaced the bulbs in this period?

That is another point I came accross one week ago. My tank is running for more or less 8 months as well. As soon as I replaced the bulbs, plants responded readly. Specially glossostigma, which probably was suffering the most with a higher water column absorbing the poor quality light from old bulbs.

Regards,
Evandro.

Too much waste in the filter or substrate will drive nitrate levels up, as well as dead/dying plant matter. Try doing filter maintenance and see if that makes a difference with your nitrates. It's possible that a deficiency is preventing the plants from using the nitrates and also contributing to algae too (besides the high lights). Are you dosing potassium and traces too?

Carissa, you may have hit the problem: if Hani is going by measured amounts of PO4 in the water, the measurement could be way off, and the PO4 very low. That would stop the plants from using the nitrates. Thus, no active plant growth, and that leads to algae.

thanks for reply, am using a ventrui reactor, DC with 4kh water,its almot going to turn yellow, the light been replaced, am using 2 CF light 55 wt each , and 2 aqua glo., i have 2 extra power head one at the upper left corner and one at the bttom right cornor
i was told it could be the water circulation , so i did trem the tank added more power heads.
picture below shows the tank before and after trimming, and a shoot of stunt plants
http://i210.photobucket.com/albums/b...cture044-2.jpg
http://i210.photobucket.com/albums/b...Picture072.jpg
http://i210.photobucket.com/albums/b...Picture076.jpg

yes am dosing kno3/po4/k/plantex. i did measurment befor i ran in to problems, i used to see nitrate drop if i dont does it 3 times week, also my po4 was around 2.

Looking at your tank photos, they look very similar to the plant density that I had before my last rescaping. I couldn't get the BBA to stop with that much plant density.

I suggest that you just dose per EI and retire the nitrate and phosphate test kits. If you want to continue to use them, be sure to calibrate them first, using solutions you know the ppm of nitrate or phosphate in. Phosphate test kits are asked to do a very hard job - discriminating between very, very weak concentrations of phosphate in the water, and they often don't do it well. And, if the plants don't get adequate phosphate the can't use the nitrate either.

i did calibrate the kits ,and thats why am using two kits of each one by lemotte and one by hagen, the tank was doing will for some time then sudden nitrate spike happened.
i will clean the filter today and replace most of the filter matirial except the biomed.
not sure what else to do?

Hani, this tank is very over grown and high very high plant biomass to say the least!

The close ups seem like pictures from a poor/low CO2 plant tank.
As plant biomass increases and becomes really high, the amount of CO2 demand goes way up also.

If more CO2 is not added, then the plants will slow(not stop) their growth, and this can lead to PO4 and or NO3 back up, rarely NH4.
Plants will start to leach PO4 and NO3 out if they are stressed from low carbon.

So you can get a spike of NO3 and assume that is what is causing the poor growth etc, rather than CO2 and providing a good trim and a stable plant biomass.

Keep the garden pruned and tidy basically and you should not have too much issue.

More plants= more nutrient/more CO2 and more light demand.
Less plants = less of these.

The algae and twisted tips look like poor CO2 in the photos.

Regards,
Tom Barr