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Cleaning my filter


Jul 11, 2003
I want to clean my Fluval 403 filter but im not really sure how (im afraid of messing up the whole bacteria thing :smile: ). How exactly should i do this do i siphon some of my tank water into a bucket and simply rinse out the media??

Thanks in advanced
Hi Rockthis,
If you do your Fluval maintenance in conjunction with a water change, you can use the water you remove for rinsing out the sponges and filters.
You rinse out the sponges a few times - the idea is just to remove loose particles and clean them some.

Correct...you want to disturb the media as little as is possible! Glad to hear everything is going so well for you! Congrats!
This is a little off the topic, but i dont want to make to many threads so i want to ask me question here.
The S.G in my tank is kinda low it went from 1.025 to 1.023. I want to get it back up but when i was making my new saltwater to put in the tank tomarow the S.G was really high (in the bucket that im mixing the water in) it is around 1.030. Should i go ahead and add the saltwater in the tank tomarow?
Hi Rockthis,

You want to avoid drastic differences between the water in the tank and the water you're adding.

I don't know how many gallons of water you're planning to change, but if you're doing a 5 gallon water change, pour off 1 gallon of the salt water you've mixed. Put this in a one-gallon water container and mark it with the sg and pH for future use. Then replace it with one gallon of RO/DI water. Measure the sg again. It should be a lot closer to what you need, but you have the extra salt water to make additional adjustments with.

Salt concentrations

From your figures (sg =1.025 reduced to 1.023, difference = 0.002) you have about 10% (2 divided by 25 = 8%) less salt in the tank water than you would like. The replacement water (sg =1.030) has 20% extra and would help get the salt level back up.
When the formula
tank water volume x 10(%) = top-up water volume x 20(%)
balances you will end up with a tank full of water at about your desired salt concentration.
e.g. 50 (gallon) x 10 = top-up water volume x 20
50 x 10 / 20 = top-up water volume
25 (gallon) = top-up water volume required.
If the more accurate figure of 8% light in salt is used the numbers are :--
50 x 8 / 20 = 20 (gallons) required
But you would need to make space for that sort of addition! - check the density between batches of new water.

I used to siphon the water to be added into the tank, by using narrow tubing the above volumes could be added slowly and allowed to mix thoroughly in the tank circulation, with no noticed problems.

I do not know what rate of change of salt concentration is safe (it will vary with the organisms in the aquarium!) but adding plain water (100% light of salt) to make up for evaporation is the most extreme difference in salt concentration that would likely to be encountered.
mike, sorry if this is off-topic but have you got a nissan skyline gtr, it's that there is a user on a uk gtr forum who has your username, he own's a skyine supposebly, if you don't know what a skyline is don't worry about it.

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