Dosing Alk and Calc - ever increasing demand?

AtisE · Dec 14, 2020

Recently upgraded the from a 40 Gallon sump-less tank to a 75 gallon with 26 gallon sump. Some of the rock came along. None of the sand. No huge colonies. Added a larger new rock structure and cycled. Used to dose 30ml Soda Ash and 30ml Calcium. Started off the new tank at about 70ml each. Well, here I am a month later and am dosing over 220ml of each and can't seem to keep Alk at 9.50 and Calc at 440. The new rock has speckles of coraline algae all over it which is good to see, but no other crazy coral growth. That seems like a HUGE increase in dosing with no real increase in the readings. What would you do next? Side note: wish the Neptune would spit out a graph for trident test readings compared to dosing amounts. Would have saved me from having to build my own chart.

Reefs and Geeks · Dec 15, 2020

Do you have precipitation anywhere? You could possibly have low magnesium and just precipitating more and more alk/ca with higher and higher doses. That does seem like quite alot to be dosing for not having large colonies. Just for a referance point, I'm dosing about 50% more than you are, however my system is about 4 times the size and is pretty full of larger colonies.

Randy Holmes-Farley · Dec 15, 2020

Unfortunately, you do not indicate exactly what you are dosing and I will just assume you are dosing my DIY recipe #1 (like BRS uses).

Assuming that's the case, the dose you are using is pretty hefty, at more than 3 dKH per day.

Did you use new sand in the new tank, or no sand? New sand often initiates precipitation of calcium carbonate. If there is sand, check it for any hardening.

I'd suggest backing off on the alk to 7 dKH, switch to sodium bicarbonate dosing to drop the pH a bit, and make sure the salinity is 35 ppt to ensure that magnesium is OK.

AtisE · Dec 15, 2020

Randy Holmes-Farley said:
Unfortunately, you do not indicate exactly what you are dosing and I will just assume you are dosing my DIY recipe #1 (like BRS uses).

Assuming that's the case, the dose you are using is pretty hefty, at more than 3 dKH per day.

Did you use new sand in the new tank, or no sand? New sand often initiates precipitation of calcium carbonate. If there is sand, check it for any hardening.

I'd suggest backing off on the alk to 7 dKH, switch to sodium bicarbonate dosing to drop the pH a bit, and make sure the salinity is 35 ppt to ensure that magnesium is OK.

Sorry for leaving some stuff out. I'm dosing Soda Ash and Calcium Chloride. I used new sand. ph is always between 8 and 8.2. I did find a handy way to display dosing against measurements. Mag was 1320 this whole week. So let the dkh fall to 7? I'm afraid switching to Sodium Bicorbonate will then drop ph lower than 8. Not to mention having 4 more bags of soda ash in the garage. Checked the sand and it looks normal. Now the coraline algae on the new rock is definitely growing fast. Believe I noticed some specks for the first time a week ago and now it's very noticeable and covering the rocks nicely. So pull back the dosing to get dkh to 7?

Crustaceon · Dec 15, 2020

It really sounds like a precipitation issue to me. I’d stop all dosing for a week and let your alk level settle on its own. Don’t worry if it lands in the 6’s. It won’t be there long term. Start over with 10 ml per day dripped VERY slowly directly into a circulation pump. Don’t just launch the dose into the tank like you’re pouring laundry detergent into the washing machine. I always add soda ash over the course of a few minutes because it is THAT prone to causing precipitation issues when added too quickly. Each day dose 1ml more & retest until you see an increase in alk level. Don’t focus on getting back to 9.5dkh quickly. 7dkh without precipitation is perfectly fine and easy to achieve in your situation and if your alk is increasing with a certain dose, it’ll likely surpass 7dkh in a very slow & safe manner anyways. Give it a month and see where that settles. If it stops lower than your target alk, up the dose by 1ml and wait another month.

Randy Holmes-Farley · Dec 15, 2020

AtisE said:
Sorry for leaving some stuff out. I'm dosing Soda Ash and Calcium Chloride. I used new sand.

Still do not know what recipe you used, so cannot really say how much alk you are dosing.

I expect the sand and its fresh calcium carbonate surfaces acted as seed crystals for more precipitation of calcium carbonate. It's a common problem.

Eventually, the sand will be coated with magnesium, phosphate, and organics that all stop calcium carbonate precipitation.

Randy Holmes-Farley · Dec 15, 2020

AtisE said:
Sorry for leaving some stuff out. I'm dosing Soda Ash and Calcium Chloride. I used new sand. ph is always between 8 and 8.2. I did find a handy way to display dosing against measurements. Mag was 1320 this whole week. So let the dkh fall to 7? I'm afraid switching to Sodium Bicorbonate will then drop ph lower than 8. Not to mention having 4 more bags of soda ash in the garage. Checked the sand and it looks normal. Now the coraline algae on the new rock is definitely growing fast. Believe I noticed some specks for the first time a week ago and now it's very noticeable and covering the rocks nicely. So pull back the dosing to get dkh to 7?

That's exactly why I recommend it. You want a lower pH. pH is the biggest driver of precipitation.

Yes, let the alk drop back to 7.

Woodneers · Dec 15, 2020

Following along on this one!

AtisE · Dec 15, 2020

Randy Holmes-Farley said:
That's exactly why I recommend it. You want a lower pH. pH is the biggest driver of precipitation.

Yes, let the alk drop back to 7.

Copy all. When you say I want a lower ph, what range are you thinking? Focusing on a ph above 8 seems to be the common goal. Should I be keeping the calcium target at 440?

AtisE · Dec 15, 2020

Randy Holmes-Farley said:
Still do not know what recipe you used, so cannot really say how much alk you are dosing.

I expect the sand and its fresh calcium carbonate surfaces acted as seed crystals for more precipitation of calcium carbonate. It's a common problem.

Eventually, the sand will be coated with magnesium, phosphate, and organics that all stop calcium carbonate precipitation.

Sorry for my ignorance on the details. I use the BRS pharma pouch for Soda Ash mixed with 1 gallon of RODI water.

Randy Holmes-Farley · Dec 15, 2020

AtisE said:
Copy all. When you say I want a lower ph, what range are you thinking? Focusing on a ph above 8 seems to be the common goal. Should I be keeping the calcium target at 440?

The more you lower the pH, the better (I would not drive it below 7.8 for long though). A drop of 0.3 pH units is about the same effect as a factor of 2 drop in alk or calcium, neither of which do you want to do.

AtisE · Dec 15, 2020

So here we go... Reduced the soda ash dosing to 20ml from 220ml per day and dkh has dropped from 8.5 this morning to 7.5 just now. also decreased the calcium chloride dosing to 20ml per day. Just hold steady and watch alk fall still, I guess.

AtisE · Dec 16, 2020

Good morning. dKh dropped to 6.59 as of this morning at 0800. No dosing for the last 24 hours. Just continue waiting? ph at 7.9 this morning.

Randy Holmes-Farley · Dec 16, 2020

I'd use baking soda to keep it at 6.5 dKH.

AtisE · Dec 16, 2020

I dosed some soda ash again and retested after 4 hours. 0.3dkh drop in 4 hours. Rechecked the return pump area and the overflow where my heater is much closer. Well... surprise surprise everything's COVERED in percipitate. It's like a little ice kingdom is being built. cleaned off the heater. will clean the return pump area as well. I'm assuming my sand is turning into rock. Any suggestions on how to get this stuff out most effectively? Trying not to cause an even bigger problem by just scraping it off the overflow wall.

Randy Holmes-Farley · Dec 17, 2020

AtisE said:
I dosed some soda ash again and retested after 4 hours. 0.3dkh drop in 4 hours. Rechecked the return pump area and the overflow where my heater is much closer. Well... surprise surprise everything's COVERED in percipitate. It's like a little ice kingdom is being built. cleaned off the heater. will clean the return pump area as well. I'm assuming my sand is turning into rock. Any suggestions on how to get this stuff out most effectively? Trying not to cause an even bigger problem by just scraping it off the overflow wall.

Aside from maybe a problem on a heater or pump, by itself it is just like rock or sand once it is covered in materials like organics that prevent ongoing precipitation, and isn't a problem to leave it there.

AtisE · Dec 21, 2020

All has been better and more stable now with a slight uptick in alkalinity since starting to dose 50 ml each of soda ash and calcium chloride. What's surprising to me, probably cause I have no idea what I'm looking at, is calcium dropping while alk is increasing. Any ideas/suggestions? Only solution I can think of is dosing more calc which now isn't matching the ratio of 1:1 with the soda ash...