Do I need to change water during cycling?

[hbpencil]

Dear all,

I'm setting up a reef tank soon (4 ft x 2 ft x 2.5ft). Can any1 advise me on the following:

1. Do I need to do water change during cycling of my tank?

2. Is it correct that once cycling is done (all parameters meet requirement after 4 - 8 weeks of cycling), do I need to do a water change before adding in my first fish? If yes, how much water should I change?

Thank you very much for you patience.

Cheers,

hbpencil

[Achilles Tang]

Water change is necessary only for the last phase where nitrate still remains high... depending on filtration setups (usually non DSB or with fully functioning refugium)... persistently high levels of nitrates can only be removed by dilution with water changes.

[hbpencil]

Thanks AT.

My tank will consists of about 100kg of live rock with DSB (5"- 6") in my refugium. The sandbed in the main tank will only be about 2 inches.

Hope that this configuration seems right.

[Achilles Tang]

Myth: A DSB in a sump/refugium can reduce NO3 in a tank many times its size.

A DSB in a refugium should be about the same size as your tank to be effective. IMO, you should do a DSB in your main tank..... if you have one for your sump/refugium, its a bonus.

[hbpencil]

Hi AT,

I've actually been thinking about having a DSB in my main tank ...... but is quite worry as I'll be having about 100kg of LR.

Do you forsee much problem?

Thanks again.

[Achilles Tang]

You have to evaluate that yourself... commonsense... if your tank walls are thin, no bracing, weak rotting stand... definitely a disaster waiting to happen!

[hbpencil]

Thanks, got it!

A DSB shall be.

[Reef23]

Sorry to haijak ur thread. If I have a 3ft tank and my DSB with a refugium is abt 40cm X 40cm. You mention that it should be the size should be the same size with the main tank. Can i compensate it with a thicker DSB? Does this works?

[jas_soh]

haro.... could someone tell me what is a DSB??? thanks....

deep sand bed my dear...

[ozy]

haro.... could someone tell me what is a DSB??? thanks....

DSB is short for Deep Sand Bed.

It is a deep layer of sand either in the main tank for the refugium, setup for the purpose of cultivating denitrifying bacteria to reduce nitrates in the tank.

And Reef23, from my understanding, the effectiveness of a DSB is proporational to the surface area. Experts, please correct me if I am wrong.