Annual Tank Cleaning for Under Gravel Systems

Use a short sleeve shirt
wash your hands and arms, making sure to rinse all soap off

Supplies needed
paper towels
filter cartridges
diatomaceous earth
new filters (if needed)
new under gravel pumps (if needed)

prepare the tanks
Move furniture out of the way
Remove tank top decorations
Place blankets on the floor in front of the tanks
Remove lights
Place lights out of the way
Place glass & hoods next to the laundry room wash tub
Remove filter caps and filter sponges. Place in a bucket.
Remove shells, corals, and rocks from the tank and place them on the blankets. Be extra careful that fish are not hiding in corals and shells. If in doubt, leave them in the tank.
Partially fill a 6 gallon bucket with clean tap water. Remove plants and place them in the bucket.
Note the levels of the water in the tanks after removing the items. That is the level you’ll need on the last day of cleaning so you can put things back without overflowing the tanks.

clean the gravel
This will take 3 to 5 days because the vacuum removes gallons of water and we don’t want to change more than 30% per day.
Stir the gravel. Push the gravel so it is sloped towards the back of the tank. After the water clears (maybe 30 minutes to one hour) vacuum the gravel into a bucket. Empty the bucket into the toilet. Repeat until you have removed 30% of the water. Be careful on the first day- the water level will be lower since you removed the rocks and corals so adjust the calculations accordingly.
Replace the water in the tanks with filtered tap water. Add 1 tablespoon of non-iodized salt per 5 gallons of water added.
Repeat this every day until the gravel is clean.

Always ensure to save some charcoal (and bacteria) when replacing the filters.
Day 1 check the filters. Fix or replace as needed.
Day 1 replace one filter cartridge.
Day 2 replace the other filter cartridge
After running the diatom filter replace both cartridges.

Under Gravel Filters
On day 1 make sure they are all still working. Fix or replace as needed.
After running the diatom filter make sure they are still working optimally. Often they get clogged with gravel during the cleaning process.

In the meantime
clean glass & hoods
clean light fixtures (leaving no chemical residues)
clean the filter sponges and caps

Decorate the tanks with rocks, corals, shells, and plants.
Replace the lights.
Run the diatom filter on each tank. Sometimes it gets clogged very soon and will need to be run several times. This might take days to complete.

They’ll be fine during all this. The only casualties I’ve had was from unnoticed fish in shells and corals and sometimes a jumper. Catch all fish for donation and get rid of them. Catch all fish in the 30 gallon quarantine tanks and place in the 100 gallon tank. Add new fish to the 30 gallon tanks.

Replace the filter sponges and caps.
Clean the outside glass


Since I use a small amount of salt in my African tanks, I have gotten shocked. I used to have salt water tanks and I got shocked even more often. Something was wrong and trying to kill me.

Let’s figure this out.  Unplug everything. Use a multimeter, set it to AC voltage, put the black probe in the ground hole of the wall socket and put the red probe in the water. Use this as a reference ground voltage. If you see  voltage greater than one volt you have a more serious home wiring issue and I’d call and electrician.  For complete gibberish about why one volt is acceptable read Ground Loops @ MIT.

Now you have to figure out which appliance is creating the shock. Plug in one appliance at a time repeating the test. Anything greater than our reference voltage indicates a problem. It could be more than one appliance, so test them all. I’ve had submersible pumps, heaters, and lights all become faulty. But more often it was due to a bad drip loop.

A drip loop should be used for every appliance in a fish tank, especially a tank with salt in it. The cord will proceed down from the tank and a loop is formed at the lowest point, then the cord proceeds upward into the socket. This prevents water from dripping down the cord and into the socket. But salt can still creep back UP the cord. Just clean the cord with a clean wet rag and then dry it off and that should solve that. If not, replace the appliance or take it to your workshop and pull out the tools and good luck.

I just installed a GFI which will break the circuit if it detects a ground fault. It will definitely happen if you get shocked, but it might also happen for other reasons even when you are not in the room. My Africans are pretty darn forgiving and I walk by my tanks a few times a day so I’ll notice if the lights are not turning on and figure out what’s wrong fairly quickly. But if you have a reef tank I recommend a power fail alarm- you can even get them that SMS or email you. Probably cheaper than replacing the stock of a reef tank many times over.

Good luck and don’t die.

Shopping Trip

I love ‘that’ place: That Fish Place – That Pet Place

Big Tank

2 Hypostomus plecostomus

Synodontis petricola – pygmy leopard catfish

1 each small tanks

2 Featherfin Squeaker (Synodontis eupterus)

small top tank

Aulonocara sp. ‘OB Peacock’

Labidochromis caeruleus – Yellow Labido he died

Aulonocara Rubescens Ruby Red Peacock Cichlid

metriaclima estherae – Red Zebra

Metriaclima pyrsonotos – Red Top Zebra

pseudotropheus demasoni pombo rocks