ALK Issues experienced user

[Randy D]

I know there is alot out there about ALK and I have red all that I can, however I am stumped on my issue, if any and need input.
BTW my tank is several years old, mostly sofites and no sandbed.

My tank has 180 gal total volume with a 30gal refug and sump in the basement. I run carbon and GFO and my evap water is saturated limewater.
my current parameters are: (I use Salifert test kits and Hanna ALK checker)
PH 7.9 to 8.1
Ca 390
MG 1260
NO3 about 20
PO4 not sure

ALK 9.4 dkh. This is my problem. I would like to be in the 11 range (to help withh cyno and some algae issues)

So I am using BRS supplements for ALK and Ca dosing Currently I am adding 400ml per day for ALK and 200ml per day for Ca. My problem is the ALK level at 400ml per day will not keep my ALK stable I really need to add more like 800ml per day to keep it where I want 10-11.

Does this seem like an excessive amount of dosing? and if so any ideas on why.

Opinions and advice are greatly needed.

Thanks,
Randy

[bertoni]

That seems like a lot of supplement to me. What's in the tank? Clams and coralline can consume a lot of calcium carbonate. Are there any signs of buildup on tank walls, the heater, or on pumps?

[Randy D]

That is why I am posting this.
I do have a lot of signs of ca carbonate buildup on all the things mentioned have to frequently clean pumps and power heads.. No clams good coraline growth. The visual look of the tank is great, except for some cyno issues which is why I want to boost ALK level

[ReefWreak]

I've never heard of high alk getting rid of cyano. In fact, recently on my tank, I had higher alk, and cyano started creeping in. I lowered alk from 11 to 8.5, and the cyano backed out (along with other nutrient control inputs). But I don't think alkalinity levels will impact cyano growth at all. It's all nutrients.

[Randy D]

Well you may be right about the ALK and cyno relationship, several articles do agree with you. my main reason for this post is to find out if my dosing amount is unusally high and why that might be.

[bertoni]

If you are seeing signs of precipitation on the tap walls, I'd suggest switching to baking soda for a few days. The lower pH often helps with precipitation problems.

[Randy D]

So really the root of my post is it unusual the amount of supplement I am dosing daily to reach my ALK dkh goal or am I trying to obtain a number that my tank conditions just will not allow? maybe I should strive for a dkh of 8 to 9 instead of 10 to 11.

[Genetics]

How much higher do you really want to go? Your calcium and all are already at supersaturated levels. I think if you want to try to get higher you need to use a dosing pump to try to have a steady supply. Or a calcium reactor but that will lower your pH.

[Randy D]

I do use a dosing pump.

[Uncle99]

Originally Posted by Randy D

So really the root of my post is it unusual the amount of supplement I am dosing daily to reach my ALK dkh goal or am I trying to obtain a number that my tank conditions just will not allow? maybe I should strive for a dkh of 8 to 9 instead of 10 to 11.

It depends on your consumption rate.
It's seems like a lot to me.

If you ALK daily consumption is say 20ppm and 800ml of whatever you use will result in an increase in ALK of 20ppm, then fine, but must be a very weak solution, or huge water.

As a reference only, my daily dosing of ALK and CA is 15ml per day in a 60g tank mixed reef. This 15ml of Seachem Fusion 2 replaces the 20ppm taken by the corals. So this concentration raises ALK 10ppm for every 7.5ml.

So as a rough, rough estimate yours is 3x mine so 45ml, but again, depends on concentration.

I would check your MG and increase to 1360, then recheck your ALK.

8.0 to 9.5 is fine, stability is critical.

[Randy D]

Yea I know it seems a lot of dosing. I am going to get my Mg up and try to shoot for 8-10 dkh and see what my daily dosing will be

[bertoni]

A dKH level of 8-9 should be fine. It'd be easier to maintain that than 10-11 dKH.

[outssider]

switch from carbonite to bicarbonate....you're getting precipitation...this change will fix it.

shoot for 8 dkh….. make sure your not low on mg …..

[Randy D]

will give the bicarbonate a try

[dkeller_nc]

The first thing to check is your magnesium test. I'd be very suspicious that it was reporting an artificially high number if you're getting precipitated calcium carbonate on a lot of surfaces, you're dosing an unusually high amount of alk solution daily, and you don't have lush hard coral growth that's consuming it.

[bertoni]

Magnesium can be an issue, but I have seen this problem reported in tanks with a good magnesium level, at least as far as hobbyist testing can provide certainty. I agree that it's worth testing, though.

[Randy D]

Will check Mg and get to 1300+. Stil not sure why there seems to be a limiting factor in ALK, maybe high indoor CO2?

[Genetics]

Originally Posted by Randy D

Will check Mg and get to 1300+. Stil not sure why there seems to be a limiting factor in ALK, maybe high indoor CO2?

It’s possible but how much traffic do you have in your house?

Is there anyway to bump up your pH? I see you use limewater. I’m assuming it’s contained in a reactor and fresh. Do you use a dehumidifier? That can quickly increase evaporation rate and increase your kalkwasser use.

[Randy D]

I know used to have high indoor CO2 when I tested many years ago, 2 to 3 times above outdoor if I remember correctly, (I have gas stove gas water heater, dog and an adult in the house most of the time) my limewater addition is saturated limewater replacing evap tank water. I do evap 2 to 4 gal/day. based on the season.

[ReefWreak]

If you're worried about indoor CO2 levels, CO2 scrubbers are readily available in the hobby these days. One more piece of equipment to pay for, maintain, and buy new media for, but an easy enough option.