New tank

[Dave0]

I have a brand new tank which was cycled using bottled ammonia, Colony and live sand for a few weeks. A week ago I added 2 clowns and 3 small frags.

During cycling, my alk started dropping and has continued- it's now down to six. I've just done a batch of newly mixed saltwater (Fritz RPM) at 10dKH.

What could be causing this drop -it can't be the coral as they are tiny wee things and the alk was dropping before I even put them in?

What should I do about it? As I see it my options:
1) Start dosing (seems a bit early in my reefing career to start having to do that!)
2) Be patient and do regular 10% weekly water changes and hope the alk goes up
3) Do a 50% water change to try and get the alk up more quickly
4) Find out what's causing the alk drop and kill it with fire

20G tank:
Salinity 35
0 ammonia, nitrite, phosphate
15 nitrate (I think this is high because I was using bottled ammonia for cycling)
No visible algae

EDIT: Looks like I've somehow double posted. No ide how to delete this thread!
Thanks!

Dave

 

[SlugSnorter]

maybe should have waited on corals, param swings might mess them up. if you make another tank wait a few week after fish before adding any corals. Also get a very small CUC (2-3 hermits) for now

did you remember to do big WC after cycling? you should do weekly 2(10%)-4(20%) gallon changes weekly if you haven't being doing so already. No tap water at all, never use it, not even a little bit, needs to be distilled or better (RODI is the best). do a water change to get your DKH back as your tank life needs it stable

 

[MaxTremors]

In new and cycling tanks, bacteria can do weird things to your Alk, you can either do water changes and slowly get it back up or dose some two part (just the Alk part if calcium isn’t low). What kind of corals do you have. If they are soft corals or even hardy LPS, they should be fine with slowly bringing the Alk back up with WCs (monitor to make sure it’s not continuing to drop). 6dkh really isn’t that low, NSW is around 7dkh, but either way, you’ll want to raise it slowly, at the fastest over a few days, but preferably over a week or two (especially if your target is higher like 10dkh), but just getting it up to 7dkh can be done in a couple days (if you’re at 6).

 

[Dave0]

maybe should have waited on corals, param swings might mess them up. if you make another tank wait a few week after fish before adding any corals. Also get a very small CUC (2-3 hermits) for now

did you remember to do big WC after cycling? you should do weekly 2(10%)-4(20%) gallon changes weekly if you haven't being doing so already. No tap water at all, never use it, not even a little bit, needs to be distilled or better (RODI is the best). do a water change to get your DKH back as your tank life needs it stable

Thanks SlugSnorter. I’ve used RO water from my LFS (I’ve also just bought a RODI filter of my own) . I did a 90% change after the cycle finished, and did a 10% change today

 

[Dave0]

In new and cycling tanks, bacteria can do weird things to your Alk, you can either do water changes and slowly get it back up or dose some two part (just the Alk part if calcium isn’t low). What kind of corals do you have. If they are soft corals or even hardy LPS, they should be fine with slowly bringing the Alk back up with WCs (monitor to make sure it’s not continuing to drop). 6dkh really isn’t that low, NSW is around 7dkh, but either way, you’ll want to raise it slowly, at the fastest over a few days, but preferably over a week or two (especially if your target is higher like 10dkh), but just getting it up to 7dkh can be done in a couple days (if you’re at 6).

Thanks for the advice. I’ve just got some softies (gps for back wall, Zoa and mushroom). I might do water changes every couple of days to slowly try and increase it. If that doesn’t work I will get some 2 part. Im aiming for 8-9 dKh, was surprised the Fritz came up as 10

 

[SlugSnorter]

Thanks for the advice. I’ve just got some softies (gps for back wall, Zoa and mushroom). I might do water changes every couple of days to slowly try and increase it. If that doesn’t work I will get some 2 part. Im aiming for 8-9 dKh, was surprised the Fritz came up as 10

this is the best way to do it, it is a really good idea. change water about every 2-3 days

 

[Dave0]

I did a 10% change and a 20% change which temporarily raised the alk (not by much) but it started falling again. It's stayed stable at 5.9 for a couple of days so I've decided to start dosing with 'baked' baking soda over the next 4 or 5 days (Using a cutdown version of Randy's recipe I've dissolved it in 500ml RODI, 7.5ml of which works out to about 1g baking soda which I will dose once a day until I hit 8/8.5dKh). Let's see what happens...