Where are the nitrates coming from?

[Reefer_madness78]

Assuming you have something similar to this, it isn't too terribly complicated.

Just fold the hose over itself to constrict the water flow when you start sucking up too much sand. There is a point were you're vacuuming detritus but not sand. You'll need to squeeze and release at certain times to manage the flow. Let me know if that doesn't make sense.

How often should I do it? If I add nassarius and or conch snails will that help?

 

[Deschutes541]

How often should I do it? If I add nassarius and or conch snails will that help?

Since you've never done it, I would only do about 15-20% of your sandbed each water change. Do that until you've completely cleaned the sandbed. Afterwards, maybe clean the whole thing once every two weeks or once a month.

Snails help but even with them, I still clean my sandbed completely once every month.

 

[Randy Holmes-Farley]

I thought reef roids would raise phosphate not nitrate. The nitrates were still 20 before I started reef roids. It may have went up some because of reef roids but it was 20 during fallow and no feeding. I'm going to do a 40% wc this week and see if that helps and see if it goes up again.

Just to clarify, ALL foods add both N and P that will contribute to nitrate and phosphate. There may be differences between the relative amounts, but but unless you are talking about something like an amino acid or omega fatty acid supplement, you should expect both.

 

[AlexG]

Based on what I am reading I am going to say the canister filter is the likely source of your nitrates with feeding the regiment being a possible contributing factor in the problem. This has more to do with what the canister filter is doing for your biologic filtration balance. Despite cleaning a canister filter it will not take away from what it is doing when it traps food and other waste. The process of decomposition inside a canister filter is rapid due to the water flow and abrasion against organic material. A canister filter is also an ideal environment for aerobic bacteria as there is a high surface area and typically high levels of oxygen. With that combination the aerobic part of the nitrogen cycle is highly efficient which quickly produces nitrates. With out a balanced level of denitrifying bacteria present which live in anaerobic environments the nitrates levels will increase.

As an example frozen mysis shrimp that gets sucked into a canister filter will be forced against a filter pad and water abrasion will quickly breakdown the mysis into dissolved organic matter which will be consumed by nitrifying bacteria in the canister filter ultimately producing nitrates as a byproduct.

That same piece of frozen mysis shrimp that falls to the bottom and settles in an area with minimal flow will also decompose but it will be a slower process to breakdown to nitrates. Its also likely that microfauna or the larger cleanup crew organisms will consume that as food allowing a food web to be supported since it is not being dissolved into the water column by water abrasion.

This is one of the reasons that I do not run filter socks or filter floss in my systems other than a temp water polish when I stir things up. (Or for a laugh to see how big I can grow sponges in a filter sock) There is plenty of bacterial living on the surface area of the rocks once a tank starts to become established.

If you plan to make any changes to your canister filter do it slowly and don't just shut if off. Maybe remove the filter pads and run without them do a water change and observe for a week or two. Then if needed start to remove the biological media from the canister filter slowly and monitor your nitrate levels. The other route would be to build a denitrifying filter that makes an anaerobic environment for denitrifying bacteria.

This paper talks about the impact of flow on the decomposition of leaves and twigs in water. The principal of what I am referring to with decomposition is the same. https://www.researchgate.net/public...g_force_for_decomposition_of_leaves_and_twigs