Maintaining Alk

[desertranger]

After my Alk dropped to between 5-6 dkh I started using BRS two part system. I have since been trying to maintain between 10-11 dkh. I have been using about 50ml for Alk every two days or so. I have about a 100gal system over all. Is that too much to be adding or am I ok. I calcium depletes at a lower rate. I just don't want to hurt anything ?

 

[PSU4ME]

Do you have a lot of corals in your tank? How/what do you use for top off?

 

[desertranger]

I use straight RO/DI with my ATO. I would say I have a decent amount mostly softies though since I was having trouble with LPS/SPS except my frog spawn that I have had for a long while now. Everything else has died off except my sunset coral which is starting to make a come back since I have been dosing. I am also running carbon/gfo.

 

[reefer gladness]

Forget the reason why but I've seen in a few places that alk should be kept in the 7-8 dKH range when dosing carbon. My LFS (vividaquariums.com) recommends keeping alk around NSW levels when dosing carbon also, they mostly specialize in SPS corals.

 

[PSU4ME]

I run bio pellets and keep mine between 7-8 so that might be right

 

[Mrsalt]

Yep I've just written a thread with that in, it seems that any form of po4 export if taken to a level below 0.03 will stress out sps and cause stn of the tissue.

 

[desertranger]

are you saying i should have some po4 in the water ?

 

[Mrsalt]

If your using a method such as carbon dosing which is ultilised to get really low nutrient levels then alk should be around 7-8, Red Sea program for growth if followed try's to maintain a po4 level of around 0.08 anything less and it stresses the corals due to the desire to run very high alk. I didn't know this till fairly recently as I had a ton of GFO running to create a very low po4 value which I always thought po4 inhibits coral growth. I struggled for months trying to figue out why my acros had stn. It was not till I started zeovit that I discuvored I needed to lower my alk to 7dkh due to running a low nutrient system that I found that out. Since then my corals have bounced back.

It's just something we all assume - get the alk high, and the po4 as low as possible for good corals but looking more in depth the two are more linked than I had imagined.

HTH

 

[desertranger]

I guess i will hold off on using my gfo for a while and see what happens.

 

[desertranger]

should i stop using carbon too ?

 

[PSU4ME]

No reason to stop the carbon usage.

 

[Mrsalt]

Why not just maintain a Lower alk? It's the easiest thing to do since the tank is almost shouting that at you?

 

[desertranger]

I will give it a try.

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[PSU4ME]

To maintain low alk the best thing to so is to find a good salt that has low alk. I use salinity by seachem. It's good quality, very consistent and alk is on the lower side. Salts like Red Sea aim for a different outcome so make sure you align your salt with you tank params.

 

[desertranger]

Should I stop using gfo and see what happens ?

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[BigAl07]

Desertranger be careful to not make too many changes too quickly. If something goes wrong you need to know what most likely caused it so it can be corrected. Keep in mind that nothing good happens fast in the ocean so make all changes slow and with a game plan.

 

[Mrsalt]

Totally agree with that sound advice BigAl. If your current alk is running 5-6 just slowly increase it to seven over a course off the next week. Don't raise it more than 1dkh a day is the general advise, so by raising 1.5dkh over a week should be fine. Then maintain it there is all I would do.

Again keep with the carbon dosing unless your getting cyano, in which case back it off bit by bit. GFO is fine, as it has got you a low po4 situation so aim to keep it around that figure.

Keep us upto date with how it all goes and you should see it on the mend.