Low nitrate question

[darkmatter_3500]

I had a recent experience with abnornal low nitrate readings on my 125 growout tank and was wondering if anyone else had this happen. I work 7 days and I am home for 7 so I always do a 50 percent water change the day I get home and the day I leave, before I did a water change last week I noticed my nitrates were maybe .5 , I even tested 3 times . They are always .20 or higher after my week of work. My ammonia and nitrates were 0 like usual. While doing the waterchange I noticed my fx5 flow was reduced to a trickle from a clogged water polish pad. I run a water polish pad and packed the other trays full of seachem matrix. I also have a xp4, ac 110 and emporer 400 on this tank that were working fine. Could the reduced nitrates be due to such a slow flow in my FX5 and anerobic bacteria in the matrix using up the nitrates?

 

[darkmatter_3500]

The reason I was posting this is I am thinking of packing my XP4 full of matrix and reducing the flow to see if it helps eat up nitrates.

 

[Terrance]

How long has the matrix been in the filter and how much of it do you have?

 

[darkmatter_3500]

I have the top 2 trays full of matrix bottom tray is a polishing pad which clogged thats what reduced flow to a trickle, and it was really barely any water coming out . I changed the pad and flow returned to normal.

 

[darkmatter_3500]

Also that matrix has been in about 6 months

 

[Terrance]

Sure lets say its matrix for now. Check parameters again before next water change. Im testing 20liters of pond matrix right now, so your feedback is great!

 

[darkmatter_3500]

Thats cool, I when I get home im filling 3 baskets in my XP4 with matrix and turning the flow down to almost nothing to see what happens, my FX5 is flowing like normal this week so I will see if my nitrates are back up like they usually are. Im going to swap the matrix in my FX5 with the ceramic rings & ehiem balls in my XP4 so I start with cycled material.

 

[darkmatter_3500]

I dont think matrix is some magic product but if the water flow is reduced enough im assuming anaerobic bacteria can grow in the pores and consume nitrate as advertised. My FX5 reduced flow by accident but my XP4 has a knob that I can manually reduce the output thats why im going to try it this time.

 

[Terrance]

Yeah its possible. I thought it was only Denitrate that required slow flow. A Seachem rep told me Pond Matrix is fine in high flow environment.

 

[Daxhua]

I'm also wondering if the matrix in my two XP filters is the cause of my low nitrate level (I think zero) or if its just my plants doing their thing. I have one basket in my XP2 half way full, two baskets in my XP4 full of matrix but my flow rate is high. I really doubt it though as I've read that denitrification bacteria only grows in water with very low water flow and low oxygen levels.

 

[Terrance]

Follow my trial. I have ~1000gph in 15g of water full of water and matrix.

http://www.aquariumadvice.com/forums/f60/pond-matrix-trial-in-fw-196466.html

I will get my matrix out of the trashcan very soon and get it inside a fish tank for better flow through all the matrix.

 

[darkmatter_3500]

I will follow it and I will post my results. I like the idea of lowering nitrates because I am gone every other week. The week im home I change the water twice and vacum the gravel so my nitrates are never sky high but I like the idea of keeping them low. Even after a normal water change the nitrates are never as low as the time my FX5 clogged.

 

[darkmatter_3500]

I got back from work yesterday, checked nitrates .20 so they came back up to normal since my FX5 was flowing normal. Today I swapped matrix in the FX5 with the rings in my XP4 and turned to flow way down , a little more than dripping out of the spraybar. After a 50 percent WC I retested the nitrates and they were .10 so that is my baseline. I will retest every 2 days and post results.

 

[darkmatter_3500]

Im back at work today and I tested the water every day this week, nitrates only got up to .15 this week and 0 ammonia and 0 nitrite. Something must be working , I thought about skipping my waterchange for the week to see what happened to the nitrates but I got nervous and changed the water since I will be gone all week. I will retest the water when I get home next tuesday.