Sand bed - High Nitrates and Zero Phosphates

[SaltyBuddha]

Hey guys,

 

Just thought I would throw this out there and see if anyone has any ideas.

 

My IM10 had a 3" to 4" sand bed since the start. About 2 years.

My nitrates always raised consistently while my phosphates constantly stayed at 0.

I also had a weird film/short hair algae growing on the back acrylic of the tank.

 

Since replacing the sand bed completely, I have seen my first phosphate reading of .03ppm in almost a year.

The film algae is also gone and nitrates are more consistent. 

 

The sandbed was obviously in a weird spot between a shallow and a DSB. 

 

Is there a phosphate dependent bacteria that could have developed in the 3" to 4" sand bed range?

 

 

 

[seabass]

Hmm...  a carbon source would be required.  Although that usually uptakes nitrate as well.  Unless your tank was creating a lot of nitrate, and less phosphate.

 

I'm really not coming up with a lot of ideas.  But something was acting as a nitrate factory, while phosphate (along with some of the nitrate) was being utilized.

 

Phosphate can bind to calcium.  That's a potential wrinkle; but in a tank that age I'd suspect it would be leaching out at this point. 

[Nano sapiens]

I had the same question a couple years back.  Purple Sulfer Bacteria (PSB), as an example, may be one of the main players as they sequester phosphate and use sulfer, as opposed to using nitrogen, in anoxic aquatic environments such as stratified lakes, intertidal zones and waste water lagoons.  Any sandbed over an inch or so would develop anoxic zones and these types of bacteria could thrive there competing, or possibly outcompeting, nitrogen utilizing bacteria causing a phosphate/nitrate imbalance.

 

Another thought I had related to Kalkwasser additions.

Since phosphate is likely to be precipitated out of solution in the vicinity of Kalkwasser additions, could this have an impact on ratios?  Typically, this sequestered phosphate would be liberated by bacterial action and again be made available, but if said bacteria were not present in sufficient numbers, or didn't have the resources available to effectively perform their functions, could this also skew the phos/trate balance?

 

Until someone actually takes a deep-dive into studying our sandbed's microbial makeup, it's still an educated guessing game at this point.

[SaltyBuddha]

On 5/27/2019 at 2:25 AM, seabass said:

Hmm...  a carbon source would be required.  Although that usually uptakes nitrate as well.  Unless your tank was creating a lot of nitrate, and less phosphate.

 

I'm really not coming up with a lot of ideas.  But something was acting as a nitrate factory, while phosphate (along with some of the nitrate) was being utilized.

 

Phosphate can bind to calcium.  That's a potential wrinkle; but in a tank that age I'd suspect it would be leaching out at this point. 

 

4 hours ago, Nano sapiens said:

I had the same question a couple years back.  Purple Sulfer Bacteria (PSB), as an example, may be one of the main players as they sequester phosphate and use sulfer, as opposed to using nitrogen, in anoxic aquatic environments such as stratified lakes, intertidal zones and waste water lagoons.  Any sandbed over an inch or so would develop anoxic zones and these types of bacteria could thrive there competing, or possibly outcompeting, nitrogen utilizing bacteria causing a phosphate/nitrate imbalance.

 

Another thought I had related to Kalkwasser additions.

Since phosphate is likely to be precipitated out of solution in the vicinity of Kalkwasser additions, could this have an impact on ratios?  Typically, this sequestered phosphate would be liberated by bacterial action and again be made available, but if said bacteria were not present in sufficient numbers, or didn't have the resources available to effectively perform their functions, could this also skew the phos/trate balance?

 

Until someone actually takes a deep-dive into studying our sandbed's microbial makeup, it's still an educated guessing game at this point.

 

I haven't been able to find anything concrete on the issue. I don't use kalkwasser but I do dose two part (ESV). Alk/Ca rise consistently with each other. 

 

It may also be the fact that I mainly feed pellets and there may be a nitrate/phosphate imbalance there. 

 

My phosphates are now back to 0 after last weeks 0.03   but I believe my new chaeto reactor is sucking them all up

Nitrates are now at 0.2 or less as well. 

 

I'm going to increase feeding with more varied foods and see what happens.

[mcarroll]

Depending on your test kit, there may be no effective difference between 0.00 and 0.03, so it could have been a mirage...testing error.

 

If you have an apparent nutrient imbalance, the fix is often to stop messing with it.

 

If you have no excess nutrients, then you also have no reason to grow macro-algae -- that's a predictable problem waiting to happen.  Either the tank or the fuge will buckle under the competition for nutrients.  That's not your goal, so personally I'd decom the macro algae until it's really needed.

 

Moving up to non-processed, whole foods would be a good move for lots of reasons -- I agree with this move.

 

What else are you doing in the management of nutrients on this tank?  Skimming?  Anything else?

[Clown79]

I had the same issue for yrs. 0 phosphate results while nitrate was sitting around 2-7.