Alkalinity decline without coral

[Cheeze]

@Cheeze what's your pH? The pH boost will be temporary. If you dose it continuously you will get a continuous pH boost, but I dont recall how much of a boost. This is what I'm going to try next: daily dosing of a small amount of sodium carbonate. I have a Neptune DOS so might try dosing tiny amounts more frequently than daily. My pH hit 7.8 yesterday. Need to 2x check pH calibration and if in spec then I've got a problem I need to solve before I get corals. Also planning to run an air line to my attic to feed my skimmer.

Hi Keith! My pH is 8.2...all my other parameters which I've been consistently testing are normal and stable, just the Alk that I never really tested too much had dipped.
I'm going to be dosing baking soda, but manually a little at a time each day, thanks to the sound advice from Randy in a different thread I had posted.

 

[Cheeze]

ime, most of the time in newer tanks especially tanks without corals, the alk is precipitating straight into the sand. i had this happen in a fowlr tank that I started with dry sand. Turned the whole sand bed into large clumps of sand, started first underneath and around the rocks, then traveled out. The Fowlr tanks I started before that with "live sand" did not do that.

My tank is a newer tank, and I did use dry sand and rock. Not seeing any clumps yet thankfully, but now I'll keep an eye out. Did you do anything to resolve or fix your sand?

 

[keithIHS]

ime, most of the time in newer tanks especially tanks without corals, the alk is precipitating straight into the sand. i had this happen in a fowlr tank that I started with dry sand. Turned the whole sand bed into large clumps of sand, started first underneath and around the rocks, then traveled out. The Fowlr tanks I started before that with "live sand" did not do that.

But then shouldn't we see Ca drop? My Ca was 450 last Dec. 430 in Jan, 435 in Feb. I just measured it and its 425. So maybe dropping a little? I know Ca drops much more slowly than alk, but is 5 ppt Ca/month and 1 dKH/month drop in alk the right ratio for precipitation? I've done four 20% water changes since last November, 1st 2 w TM Pro, last 2 w HW Reefer.

 

[keithIHS]

@Cheeze pH 8.2! I wish! Sigh. I'd better calibrate my pH probe. You should too. pH is determined by alk and CO2, and it's unusual to have a pH of 8.2 with low alk unless you're getting fresh air to your tank.

 

[Miller535]

But then shouldn't we see Ca drop? My Ca was 450 last Dec. 430 in Jan, 435 in Feb. I just measured it and its 425. So maybe dropping a little? I know Ca drops much more slowly than alk, but is 5 ppt Ca/month and 1 dKH/month drop in alk the right ratio for precipitation? I've done four 20% water changes since last November, 1st 2 w TM Pro, last 2 w HW Reefer.

I do not remember what the ratio is. @Randy Holmes-Farley in one of his articles gives an approximation of how much cal to alk in a ratio. But 5ppt Cal and 1 dkh for a whole month does not sound odd to me.

What I think happens with new tanks, especially ones started with dry sand. Early on precipitation happens until the sand reaches some kind of saturation, and then it stops. And people then assume it was from the tank maturing when it was just precipitating. Which I think is what Randy was saying earlier.

 

[Randy Holmes-Farley]

I do not remember what the ratio is. @Randy Holmes-Farley in one of his articles gives an approximation of how much cal to alk in a ratio. But 5ppt Cal and 1 dkh for a whole month does not sound odd to me.

What I think happens with new tanks, especially ones started with dry sand. Early on precipitation happens until the sand reaches some kind of saturation, and then it stops. And people then assume it was from the tank maturing when it was just precipitating. Which I think is what Randy was saying earlier.

That's surprising it is even that close over such an extended period and with hobby kits.

Exact ratio for pure calcium carbonate is 2.8 dKH for each 20 ppm of calcium, or 7.1 ppm calcium per 1 dKH.

In a real reef tank, magnesium gets into the crystal in place of some calcium, dropping it to 18-20 ppm calcium per 2.8 dKH, or 6.4 to 7.1 ppm Ca per 1 dKH.

 

[Miller535]

That's surprising it is even that close over such an extended period and with hobby kits.

Exact ratio for pure calcium carbonate is 2.8 dKH for each 20 ppm of calcium, or 7.1 ppm calcium per 1 dKH.

In a real reef tank, magnesium gets into the crystal in place of some calcium, dropping it to 18-20 ppm calcium per 2.8 dKH, or 6.4 to 7.1 ppm Ca per 1 dKH.

7.1 ppm cal to 1 dkh alk, with him measuring with hobby level kits of 5ppm to 1 dkh sounds pretty dead on then.

 

[keithIHS]

That's surprising it is even that close over such an extended period and with hobby kits.

Exact ratio for pure calcium carbonate is 2.8 dKH for each 20 ppm of calcium, or 7.1 ppm calcium per 1 dKH.

In a real reef tank, magnesium gets into the crystal in place of some calcium, dropping it to 18-20 ppm calcium per 2.8 dKH, or 6.4 to 7.1 ppm Ca per 1 dKH.

Well OK! That's well within the margin of error for measurement! This is great, thanks for your help!
To clarify: likely sinks for alk without corals and macro inverts are:
Precipitation, especially in sand
Consumption by unseen inverts
Consumption by bacteria
Consumption by algae
Any others?
@Randy Holmes-Farley and @blasterman and @Miller535 if any of those are wrong or insignificant, please say so.

 

[Randy Holmes-Farley]

Well OK! That's well within the margin of error for measurement! This is great, thanks for your help!
To clarify: likely sinks for alk without corals and macro inverts are:
Precipitation, especially in sand
Consumption by unseen inverts
Consumption by bacteria
Consumption by algae
Any others?
@Randy Holmes-Farley and @blasterman and @Miller535 if any of those are wrong or insignificant, please say so.

Algae do not consume alkalinity or calcium, unless it is an unusual type that calcifies, such as halimeda.

Bacteria only consume alkalinity if they are processing ammonia into nitrate (ignoring sulfur denitrators; you'd know if you had one). If nitrate is stable at any level, this alk change is not significant because the consumption of the nitrate gives back exactly the alkalinity consumed making it.

Dosing nitrate adds alkalinity.

 

[keithIHS]

I happily stand corrected
Alk (and Ca) are precipitating into the sand.
To @Cheeze 's question, is the solution to clumping sand (and alk drop) to stir it periodically and get it live asap w bacteria, seeding w other live sand, sand-stirring critters, etc.?

 

[Randy Holmes-Farley]

I happily stand corrected
Alk (and Ca) are precipitating into the sand.
To @Cheeze 's question, is the solution to clumping sand (and alk drop) to stir it periodically and get it live asap w bacteria, seeding w other live sand, sand-stirring critters, etc.?

Stirring it prevents hardening, but may not prevent precipitation.
Getting it coated with organics, bacteria, magnesium, and phosphate will slow or stop precipitation.

 

[Miller535]

I happily stand corrected
Alk (and Ca) are precipitating into the sand.
To @Cheeze 's question, is the solution to clumping sand (and alk drop) to stir it periodically and get it live asap w bacteria, seeding w other live sand, sand-stirring critters, etc.?

When I had the clumping problem I would use a python and do weekly small water changes. The vacuuming of the python seemed to prevent it from clumping. And to Randy's point eventually organics probably covered the sand. Eventually I stopped regularly vacuuming the sand and the problem did not come back.

 

[keithIHS]

I vacuumed my sand during my 1st two water changes but then seeded my sand w sand from PacificEast Aquaculture. I didn't want to interfere w the growth of the critters so I didn't vacuum the 2nd two times. Maybe the thing to do is stir it gently to see if there's any clumping, break up any clumps, and not vacuum when changing water. What do you think? Any other way to encourage biodiversity in the sand?

 

[Miller535]

I vacuumed my sand during my 1st two water changes but then seeded my sand w sand from PacificEast Aquaculture. I didn't want to interfere w the growth of the critters so I didn't vacuum the 2nd two times. Maybe the thing to do is stir it gently to see if there's any clumping, break up any clumps, and not vacuum when changing water. What do you think? Any other way to encourage biodiversity in the sand?

Manually stirring is fine too, does not have to be vacuumed, I just found that the easiest way for me.

There is a place online that sells critters specifically for sandbeds and keeping them stirred and for diversity. This is their website,

: : : : Indo-Pacific Sea Farms : : : :

Indo-Pacific Sea Farms produces captive-bred marine life for healthier reef aquariums: invertebrates, detritivores, live sand, snail grazers, amphipods, beneficial worms, macro algae, plankton, corals, coral food and beneficial bacteria.

ipsf.com

I have heard good things about them but I must add that I have never PERSONALLY bought anything from them.

 

[keithIHS]

Thanks, I'll check them out. I've bought from ReefCleaners and PacificEast, but always good to have more options. Thanks again.

 

[timry2]

Ive used IPS Farms, get the pick 9 for 99. Special if they still have it. The snails, reef amphipods, micro stars and the mama mia worms. My tangs did not care for any of the tang heaven, but its worth a try if you have Tangs.

 

[ReefDreamz]

I think the algae in my refugium is consuming the alk. I've been growing GHA, sort of by accident, in the refugium because everyone seems to be out of chaeto. So I just let the GHA grow. When I have lots of GHA, the alk seems to drop about 0.5/wk. I harvested most of the GHA and the alk drop was less. Also, if my alk is above 9, it drops much faster. If I let it get down to 8.5, it doesn't drop nearly as fast. I haven't been rigorous about testing all this: I've been changing some other things like fuge light schedule and intensity, salt brand, amount of food into the tank, adding fish, etc., but I really think it's the algae consuming the alk and the consumption rate increases with increasing alk. No precipitation by the way, and calcium is unchanged.
I just harvested GHA again and added sea lettuce and gracilaria to the sump, so it will be interesting to see what happens...

I am experiencing this exact same scenario.
Tank is a couple months old
Started with dry rock/dry sand
Zero corals and not a speck of coralline algae
No worms or inverts or algae
Nitrate has been stable at 15
Magnesium has been stable at ~1400 ppm for weeks
pH fluctuates between 7.8 and 7.93 depending on if the windows are open
Calcium seems to go up and down between 420 and 400 inversely with alk changes
Alk is dropping 0.5 dkh/week and if I bump it up over 8.5 dkh with carbonate it drops much faster (0.5 dkh/day)
I'm not seeing any noticeable precipitation on heaters

If the consensus here is that the dkh is dropping due to calcium carbonate precipitation on the sand, is there even any reason to dose alk and try and keep it stable or should I just ignore it until I've added coral/see coralline algae?

Also if the OP is still around did your alk ever stabilize?

 

[keithIHS]

My alk consumption has declined, possibly stopped altogether. Im not sure though because I've been dosing nitrate (to prevent dinos) which has raised alk. I just yesterday switched to dosing ammonia so alk won't be raised. My tank is 2 years old, and still no coral (and only the tiniest insignificant amount of coraline).
Stability is key and you'll need to dose and regularly measure alk anyway for coral, so I think it makes sense to maintain your chosen level. But I'm a noob so get confirmation. Also Ca will precipitate as well, though much more slowly. And even Mg also but I have had to dose only once or twice in 2 years.
BTW, please do yourself a favor and measure nitrate and phosphate and make sure they don't go to zero. Dinos are truly awful.

 

[keithIHS]

I really suggest getting the Hanna low range phosphate tester. I'd also suggest adding some biodiversity, like IPSF live sand activator and wonder mud. Consider also getting copepods and maybe amphipods. I was desperate because of dinos so I added the live sand right into my DT, but it's safer to set up a small quarantine tank to keep an eye on it for pests and to let any fish disease die out (81 deg F for 45 days). I've had a couple of close calls with Aiptasia, and don't know if it was IPSF, GARF (another source for biodiversity), or someplace else. I did finally defeat the dinos, and now I've got a turf algae problem.
A couple of other comments on your post. +/- 10 points on Ca may be measurement error and coincidental anti-correlation with alk. My pH was consistently low, 7.9-8.0 for the 1st 9 months. It then slowly rose to 8.3-8.4 over the next year and a half. I calibrated my Neptune Apex probe once about a year ago and need to do it again. I'm trying to maintain the following parameters salinity - 35; alk - 9; NO3 - 5; PO4 - 0.05; Ca - 440; Mg - 1350. Everything but alk is really close. Alk is currently 10 due to nitrate dosing. I have no precipitation on heaters and pumps.

 

[ReefDreamz]

I really suggest getting the Hanna low range phosphate tester. I'd also suggest adding some biodiversity, like IPSF live sand activator and wonder mud. Consider also getting copepods and maybe amphipods. I was desperate because of dinos so I added the live sand right into my DT, but it's safer to set up a small quarantine tank to keep an eye on it for pests and to let any fish disease die out (81 deg F for 45 days). I've had a couple of close calls with Aiptasia, and don't know if it was IPSF, GARF (another source for biodiversity), or someplace else. I did finally defeat the dinos, and now I've got a turf algae problem.
A couple of other comments on your post. +/- 10 points on Ca may be measurement error and coincidental anti-correlation with alk. My pH was consistently low, 7.9-8.0 for the 1st 9 months. It then slowly rose to 8.3-8.4 over the next year and a half. I calibrated my Neptune Apex probe once about a year ago and need to do it again. I'm trying to maintain the following parameters salinity - 35; alk - 9; NO3 - 5; PO4 - 0.05; Ca - 440; Mg - 1350. Everything but alk is really close. Alk is currently 10 due to nitrate dosing. I have no precipitation on heaters and pumps.

Oh I've been doing everything I can to avoid Dino's. Already been dosing pods and live phyto, dosing AF life source mud, and added Aquabiomics live rock rubble, testing nitrates and phosphates religiously every other day. Nitrates are sitting at 15-16 and phosphates at 0.05. I'm letting the skimmate drain back into the sump to keep things dirty for now.

My pH is also low, it was 7.9-7.8 but I added a CO2 scrubber to my skimmer and now it's 8.0-7.9. What I still don't understand is what the heck is consuming alkalinity. I stopped dosing any alk or Ca 48 hours ago just to see what would happen and my alk dropped from 8.6 to 7.7 while calcium dropped from 410 to 384.

Again, no coral, no coralline algae, nitrates are not rising, Mg is steady at 1400, I don't see any precipitates on heaters or pumps...I just don't get it....where is the alk going?