Lower nitrates in a saltwater aquarium: awesome sandbed vacuum technique

This is a great tip on how to lower high nitrates in a saltwater tank by keeping your sandbed clean.

This tip will lower nitrates in a saltwater aquarium for beginners using an awesome sandbed vacuum technique to vacuum your saltwater tank’s sandbed.


This tip will not only help to lower nitrates in your saltwater aquarium, but will allow you to vacuum your sandbed forever without using buckets.

Along with weekly water changes of at least 10% in your saltwater aquarium, you need to vacuum the surface of your sandbed.

Vacuuming the surface of your saltwater tank’s sandbed removes all the uneaten fish food and fish waste from your saltwater aquarium.

It is very important to remove all uneaten fish food and fish waste from your saltwater tank so it does not rot, which will cause excessive nutrients to build up, causing bad things such as phosphate and nitrates. Phosphates and nitrates are bad for saltwater fish, corals, and your saltwater tank as a whole.

How to vacuum your saltwater tank’s sandbed

Traditionally, for years, saltwater aquarium hobbyists have vacuum’d the surface of their sandbed using a syphon, which sucks water out of the aquarium, filling a bucket. Before the bucket is filled, the syphon is stopped and the water is dumped in the street or down the drain.

This technique is great but limits the saltwater aquarium hobbyist in how much saltwater can be removed at a time (limited by the size of the bucket.)

Checkout this video from my YouTube channel, Rotter Tube Reef, for an easier and faster way to remove water from your saltwater tank.

Since I no longer use sump socks in my saltwater aquarium sump, I purchased a small canister filter for water changes.

Normally a canister filter is used to filter an aquarium. I use a canister filter to vacuum my sandbed. The part of the canister filter that sucks water from the saltwater tank into the filter is used to vacuum the surface of the sandbed and the other end, where the filtered water comes out, goes right back into the saltwater tank’s sump.

This technique for vacuuming a saltwater tank sandbed allows me to vacuum the saltwater tank’s sandbed forever, and, suck up any uneaten food or fish waste from the rocks as well.

Things to do when vacuuming your sandbed

  • Aquascape your rock work in your saltwater aquarium to make sure water is flowing through and around your rocks, allowing the nasty stuff to circulate out of your tank.
  • Replace your sump socks and filter media every few days. It’s important to replace filter media and sump socks for your saltwater tank’s filtration to work its best! You don’t want water being filtered through filter media that is holding a ton of fish waste and uneaten food!
  • If you use foam as a filter media in your saltwater aquarium’s sump to catch debris, you must rinse that out at least once a week to prevent bacteria from feeding on the detritus (fish waste) that collects, causing a nitrate factory to start!
  • Vacuum your saltwater tank sump using a canister filter to remove all the uneaten fish food and fish waste that collects. This fish waste and uneaten fish food will break down in your water column and cause problems for your saltwater aquarium.

When doing a water change, remember to clean all areas of your saltwater aquarium. Vacuum your sandbed, replace filter media and blow off the rock work (rock scape) in your saltwater aquarium. People use a turkey baster to blow off uneaten fish food and fish waste from rocks.

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