Reef Aquarium Diary - Part 3 - Cycling


So its now around a week since we filled the tank with RO Water, added salt and turned the pumps on. With the overall volume being approx 700 litres approx 30kg of reef salt was added which took a good few hours to dissolve.
The Carib Sea live sand was also added and this really clouded the water! there was even a scummy residue but this all cleared up after a few days.


I was pleased to find that all the plumbing has held out and fingers crossed no major issues, I did notice that the return line had a slight drip on one of the connectors but that's an easy fix and it was because I had decided not to glue every piece until It was checked.

The 2 heaters brought the tank up to temperature overnight to around 26 degrees c.

A day or two later I added some pieces of rock and rubble from the existing tank into the sump. I put them in mesh bags so I could move them around easily in future - these should help seed the tank with the all important good bacteria.
For good measure I also added an entire bottle of Doctor Tims bacteria supplement to kickstart the biological process. Then half a 125ml bottle of Brightwell bacter7, I had heard good things about these products so thought they were worth a try.

good bacteria saltwater aquarium

Bacteria Supplements to kickstart the cycling of the tank.


I added a very small pinch of pellet and some liquid ammonia as food for bacteria. At this stage I have not added a skimmer , algae refugium or turned on the carbon / phosphate reactors as I want some waste to accumulate in order to get the bacteria population going.
I had some alfagrog ceramic media lying around so filled 2 or 3 large mesh bags with this and chucked them in the sump for another bit of extra surface area for bacteria.

So with the bacteria from the live sand, 2 liquid supplements and some already mature live rock a good population should now be getting established!
I will just leave the tank to do its thing for next few weeks and take some tests to see how the biological cycle is going.

Keep in mind that I have a lot of fully mature rock that will go in from the other tank on moving day.


Corals from the old tank will be moved across in a few weeks.

I just wanted to make sure the system had a good start and if possible want to avoid unsightly algae blooms which tend to come in stages with new tanks, Apparently the bacteria supplements help with this and create a kind of bio film on the virgin rock surfaces that might otherwise be taken over by algae.

So not rushing anything, I want o ensure the new tank has completed its own biological cycle and the parameters are good before transferring any live stock. There are also one or two other bits of gear needed such as wavemakers and a Seneye reef monitor. 

soft coral tank

the old tank - now on its last legs - and without a sump - I love the sump on the new tank - no more skimmer sticking out the top! and plenty of room for a refugium too.

So the idea now is to match the new tank with the old tanks parameters as close as possible which should make the final transfer of fish and corals as stress free as possible for the animals!

essential test kits for reef aquarium

Testing, Testing 123! - when starting a new aquarium is probably the most important time to test all parameters - Here we have the main ones being NITRATE / ALKALINITY / SALINITY digital / PHOSPHATE Hanna digital / AMMONIA & PH....

marine aquarium test kits

I hadn't tested the old tank for a while and was slightly surprised at some of the test results, so I did a fairly large water change to improve water quality on the old tank, probably the last time I will ever do one on this aquarium.

reef tests during cycling of tank

I'm very happy overall with how everything has gone and its been nice not to rush it, I'm normally very impatient!. I was surprised how quiet the overflow was once I tinkered withe the gate valve. Thinking I do need another bag of sand though, mainly for aesthetic reasons.

the current parameters:



existing for comparison

ALKALINITY  8 dkh 7 dkh
PH  8.1 7.9
Specific Gravity  1.025 1.024
Temperature  26c 27c
AMMONIA  <0.5 Nil
NITRATE  5 - 10 Mmg/l 20 mg/l (water change!!)
PHOSPHATE nil 72 ppb = 0.220 ppm *


*My Hanna phosphorus checker measures in PPB (its the Ultra Low Range version) you multiply by 3.066 and then as the phosphorus is in ppb would divide by 1000 to get PPM (Parts per million)

Its worth mentioning that home test kits, even the digital ones are not 100% accurate and are susceptible to user error and other factors - however they give you a very good idea of how your tank is progressing. A calcium & magnesium test kit will also be handy in the future; especially if I intend to keep  more SPS and Hard corals. The digital testers still require you to add re-agent, shake etc.. but at least the end result is given for you, taking some of the guesswork out of comparing colours by eye!

As you can see from the readings on the new tank; the presence of nitrate (the end result of the nitrogen cycle) indicates bacteria is processing waste which is a good sign!

The higher nitrate and phosphate on the old tank is due to me neglecting it whilst working on the new aquarium! - I have since performed a water change and changed out media to get the levels a little lower - even though they should be pristine water quality when transferred to the new tank.

I am going to remain patient and keep monitoring, I guess it will be time to move the livestock soon in the coming weeks😊


look what just turned up! - Chaetomorpha algae for the sump (as it grows it should suck up waste, lowering nitrates and phosphates)

Chaetomorpha algae filter sump setup chamber


sump growlight

to be continued..............

next installment here - PART 4 with video of fish and corals that will be going into the new aquarium