Lowering Nitrates

[fixedwing]

Hello All,

I have a 140 Gallon fish only tank and have got to a point where I enjoy the amount of fish in the tank and I have no plans of adding any additional members. I believe I maybe on the edge of having too many fish (6 mid –large size and about a dozen small size fish). My fish don’t seem stressed at all and have plenty of hiding spots (appx. 150lbs rock), but my problem is I’m beginning to see that I have to do water changes more frequently. I would like to keep my water changes to about once a month and lately it seems like I’ve been doing changes about twice a month. I don’t like my Nitrates getting above 10 ppm.

My question is what is the best way to help reduce nitrates? I know plants will help, but specifically what kinds. Just to inform you I have had copper in my tank and I don’t want to purchase items that will die from contacting copper. I don’t think plants will die, but I’m not sure and just wanted to state it. Ultimately, I’m just trying to have a setup that will keep my nitrates down for a longer amount of time.

Thanks in advance to any advice.

 

[jaabc]

ive been considering getting some mangroves. ive also heard of a guy that put 1 ml in his 125g tank of vodka and he said that helped alot. very experimental im sure.

 

[DaveJ]

Hey guys...

Let's break this down into two issues.. nitrates and then handle the water change issue.

Nitrates can be reduced a number of ways:

One is more frequent water changes.

Growing macro algae to soak it up, then by trimming the algae and tossing it away, it removes it from the system.

Nitrate reactors, such as sulphur or other bacteria based systems. These are basically media filters with a low O2 zone in them that allows de-nitrifying bacteria to grow and process nitrates more efficiently.

Vodka or other carbon source methods. These provide carbon to bacteria, which in turn processes nitrates and breaks them down.

Increased skimming either by using a larger skimmer than 'recommended' for your system or skimming wet.

Careful monitoring of food that goes into the system. Smaller amounts, or amounts that fed more often, in smaller amounts, so more is eaten etc.

You want to also make sure that you are properly maintaining the tank, this includes vaccuming sand well and that you don't have a 'tweener' bed. This is a sandbed of between 2-4". If you have less than 2" that is a shallow bed and vaccuming it well each water change will help, along with blowing off rocks etc to remove detritus. If you have more than 5", you should have a DSB and nitrates shouldn't be an issue if you have enough surface area working for you. If you do have DSB and still are getting nitrates you will want to make sure your bed is functioning well and has enough bio-deversity to handle your system.

If you have a bare bottom system, you want to make sure you are getting all the detritus up off the bottom and out from the rocks, you do this by siphoning it out with each water change and blowing it out from under rocks etc with a powerhead as you are doing water changes.

Now comes the issue of water changes. You do water changes for more reasons than lowering nitrates. Water changes also allow you to pull out other waste products and chemicals in the system. It also helps replace trace minerals etc that your tank and livestock consume over time. Regardless of which nitrate reduction method(s) you employ, you need to also maintain regular water changes. It may seem like a pain or a waste of salt etc, but believe me, it is a vital operation to undertake.

If you are having nitrate issues, you will also want to check your source water and make sure you are using RO/DI filters that are not overdue for a change.

On the mangrove topic... People have used mangroves as a method to reduce nitrates, but the number of them required to have an impact is rather large. The effective systems are often quite large and contain a pretty large number of them. Just a few of them won't do much at all, other than add something interesting to look at.