Likelihood of Barnacle Cluster causing Alkalinity to Increase

[EricR]

What is the likelihood that a decaying/dissolving, natural, barnacle cluster would lead to alkalinity constantly increasing with NO dosing?
*I've read lots of other threads with potential sources of alkalinity increase but would like to focus on the barnacle cluster for now

Barnacle cluster purchased from local beach shop and appeared to be natural with no bonding.
Added 1 year ago,,, some of the barnacle shells have collapsed over time.
*I assumed either I or something in the tank just broke them but now I'm wondering if they're actually dissolving

Pictures then additional details...

1 year ago:

Today:

Additional details:
- 40 gallon tank with no sump running since 10/2021 (tank transfer from 6-8 month old 37 gallon)
- Best guess at actual water volume is roughly 30-32 gallons
- NO dosing,,, soft corals only with weekly 10% water changes (((rarely test alk in new saltwater but around 8 dKH whenever I have)))
- Tank had been maintaining 8-8.5 dKH on its own with just water changes
- Alkalinity increase seemed to start (gradually) about 1 month ago
- Alk increases roughly 0.7 dKH per week,,, got as high at 10.5 dKH
- I'm using Sodium Bisulfate in new water change water to get to 1.5(ish) dKH and doing frequent, small water changes to bring it down
*Nitrates have been stable forever in the 8-10 ppm range,,, was dosing phosphate daily for a long time to maintain 0.06-0.08 ppm but recently stabilized so no longer

Will buy a new barnacle cluster and replace but dreading the thought of freaking out my blenny and having him go for an escape jump.

 

[Townes_Van_Camp]

.

 

[Randy Holmes-Farley]

It seems unlikely to me that the barnacles are a big part of it, if they are real.

Do you use ro/di?

 

[EricR]

It seems unlikely to me that the barnacles are a big part of it, if they are real.

Do you use ro/di?

Thanks,,, if it's really unlikely, I likely won't change it out.

0 TDS RO/DI -- BRS 6 stage with Aquatec 8800 booster.

My other guesses for potential sources at this point are:
- Seachem Matrix in HOB since 1/2023 (only because it came with a Tidal 110 filter I swapped in) -- no idea what it's composed of
- Half dry rock (from 10/2021) that was sold as reef rock and looked like Marco Rock but can't remember where I bought it (online) so no way to go back and research if it has any cement or similar make-up although I don't think so
- CaribSea dry Special Grade Aragonite sand (10/2021)

I'm not a frequent pH tester but have tested a lot more recently since this issue started:
Always pH 8.1-8.2

I have it in my mind to test potential sources, one at a time, in small test tank to monitor for alk increase but have been too lazy so far.

 

[Randy Holmes-Farley]

Yes, testing samples in a small amount of seawater could be a useful tool.

 

[santeeeyyy]

does anyone know what that white dots are that are stuck on the side of the glass?

 

[EricR]

does anyone know what that white dots are that are stuck on the side of the glass?

In my tank pictured above, those are mostly spirorbid worms.

 

[EricR]

Randy (or anyone), is salinity increase an expected side-effect of using Sodium Bisulfate to decrease alkalinity in newly-mixed saltwater? (I'm currently hitting something in the range of 0.2-0.7 dKH with each mix)

*obvious guess would be evaporation due to heavy aeration but I've taken measures to capture/reclaim evaporated water in my mix and the salinity increase I've been seeing is a little more dramatic than I would have expected (over the course of maybe 3ish days)

...all of the above relates to new water mixing in a bin,,, not anything to do with introduction into tank

 

[Randy Holmes-Farley]

It will give a very small salinity increase that I do not think you’d be able to detect, even after a number of uses. The salinity rise is similar to the rise from using a two part to boost alk by the same amount you were dropping it here.

 

[EricR]

I never figured out the source of my alkalinity increase after testing individual suspects.
This post will be about testing sources — comments about testing flaws or other testing suggestions welcome.
Next post (at some point) will likely be focused on what my options are moving forward.

I tested all of the following (individually/separately) from DT at 1.5 weeks minimum for each:
Top off with water from ATO container, Seachem Matrix, small rocks that started as dry 2 yrs ago, sand.
*testing details at bottom of post

I did NOT test:

• Equipment (feels unlikely) — 2x Eheim glass heaters (in use 1-3 yrs), Seachem Tidal 110 with Sicce pump (in-tank), AI Nero 5
• PetCo aquacultured live rock — already coralline encrusted when purchased and in my tanks for 2.5+ years now,,, never out of water. *not easy to test since they’re large pieces, each of which has coral mounted (roughly half of my DT rock consists of this)
• Barnacle cluster — haven’t found a replacement with deep enough cavities to match current one that blenny likes,,, also Randy said unlikely

Quick reminders:
- 40 gallon tank with no sump running since 10/2021 (tank transfer from 37G tank running 6-8 months)
- Alkalinity increase seemed to start 7/2023,,, at least this is when it became sufficient enough to be noticeable

Testing Details
——
6 gallon tank with HOB power filter (no media) and heater, started with water change water from DT.
Tested the following (individually/separately) for minimum of 1.5 weeks each with no alkalinity increase noted:

1. Top off only with water from DT ATO container (just being methodical)
2. Seachem Matrix from DT HOB that was added 1/2023 — stuffed most into test tank HOB but about 1/3 didn’t fit so just laid at bottom of test tank near HOB inlet
3. Small rocks from dry rock batch that went into DT during tank transfer 10/2021 — roughly half of my rock work consist of this
4. Sand from DT covering about 1/3 of test tank bottom in fenced off area at about 1”-1.5” depth (roughly similar to DT sand depth but maybe a bit less) — sand tested for 3 weeks since I guessed this to be most likely source of problem

Potential test flaws?

1. Dry rock (#3 above) — maybe I didn’t try enough rock but pulled all I could that didn’t have corals mounted — rough guess would be something like 1/8 of total dry rock mass tested
2. Sand — there are some small areas in DT that never get touched (like one back corner and a couple of spots underneath rock caves/pass-throughs and I was NOT easily able to pull sand from those areas to test
3. PetCo aquacultured live rock mentioned above as “did NOT test” — seems unlikely though given the amount of time it has been in my tanks

…post was probably too long for anyone to really pay attention,,, sorry,,, oh well

 

[EricR]

Finally swapped out my barnacle cluster as last ditch effort.
Tested old cluster in test tank for 12 days with no alkalinity increase.
*tore down test tank today after running it for 2.5 months without ever figuring anything out,,, so much for that

 

[Randy Holmes-Farley]

Thanks for the update!

 

[EricR]

Could dosing Seachem Reef Iodide be a source of alkalinity increasing?
Only ingredient listed is potassium iodide

*too soon for me to make any hard assessment but my observations so far are pretty compelling

 

[Randy Holmes-Farley]

Could dosing Seachem Reef Iodide be a source of alkalinity increasing?
Only ingredient listed is potassium iodide

*too soon for me to make any hard assessment but my observations so far are pretty compelling

Not if those are the only ingredients.

 

[EricR]

Not if those are the only ingredients.

Thank you. I was going to feel like a complete idiot if it was a known (and well documented) fact that the two go hand-in-hand in some kind of inverse relationship.

*will post details if my strong (current) suspicion continues to match my observations over a longer period of time

 

[EricR]

Tangent chemistry question -- is there any problem with the following plan:
- already have 20 gallons of fresh/new saltwater mixed with sodium bisulfate to 1.7 dKH
- plan to use ESV B-Ionic "Alkalinity" component to raise that back up to around 8.5 dKH
- is there any chemical effect that I should consider (from sodium bisulfate then, days later, ESV "Alkalinity" adjustments)?

*note - in case any effects on Calcium/Magnesium are expected (in new mix):
- DROP is not really a concern to me
- EXCESSIVE RISE may be

 

[Randy Holmes-Farley]

Assuming this is a one time plan, the ESV or baking soda are both fine alternatives to boost the alk.

 

[EricR]

Assuming this is a one time plan, the ESV or baking soda are both fine alternatives to boost the alk.

Thank you, sir.
Yes, one time plan.
Already mixed the water to low dKH as part of my process that I had settled into (for fighting increasing DT alk over many months),,, and then my tank alkalinity suddenly stopped rising.

*thanks for the baking soda reminder,,, have unopened ESV 2-part that was a gift that I never even opened (since never needed) so will probably go with that.
...pretty sure that stuff doesn't expire (or lose potency when sealed) but will double-check that

 

[EricR]

Could dosing Seachem Reef Iodide be a source of alkalinity increasing?
Only ingredient listed is potassium iodide

*too soon for me to make any hard assessment but my observations so far are pretty compelling

Forgot to update here -- my speculation that dosing Seachem Reef Iodide could be the source of my alkalinity increasing was ill-founded.
*must've forgotten to log a low alk water change or 2 during a busy week or something like that -- the coincidence of stopping iodide dosing and me suddenly becoming negligent in my logging during the same week is kind of odd,,, but stranger things have happened

My alkalinity continues to rise at a pretty steady 0.2 dKH daily,,, and I'm still just counteracting with LOW alkalinity water change (using Sodium Bisulfate) every 3 days. Works but not convenient so I really need to come up with a better method of controlling this or, better yet, find and replace the source.
*sand replacement is my current thought but not looking forward to it and obviously won't help if soft coral nitrate consumption is my primary issue (which I don't know how to verify/validate)

 

[Randy Holmes-Farley]

If this keep going, and you doo not add creatures that use alk, then putting the bisulfate in your ATO may be a fine plan, assuming it is made of materials that can withstand low pH.

Can you list any foods that you use?