Aragonite sand

[Miller535]

I have two tanks. One brackish tank, and one saltwater tank. Both that I've had for about 2 years. I put aragonite sand in them so that it would maintain the ph for me. But I have noticed the ph has been dropping over time. And now I have to put ph adjuster in every water. Does aragonite degrade over time? And if so what can I put in to
Maintain my ph?

[Salmon]

Yes aragonite "degrades" over time. It does this to bring your pH up as well as the hardness of your water.

[RTR]

But your handling of the issue is incorrect. You should periodically add just a bit more aragonite substrate (~1/4") every six months to one year plus intervals.

The benefit to aragonite it that it does dissolve a bit and replaces exactly the materials used up from the water column. Unless the "pH adjuster" is a carbonate/bicarbonate solution, it is really not doing the same job and be harmful to the tank's normal operation. Unless you know exactly what the added material is and how it works chemically, you are likely facing instability and potential tank crashes.

You may not be doing enough water partials to support the SW chemistry with your particular bioload and filtration processes. That varies from tank to tank, so exact replacement or supplement schedules for aragonite are highly personal and individual. They do vary with the bioload.

HTH

[Miller535]

Both of my tanks I do a weekly water change. My brakish tank has two f8's in it so I do %50 water change every week. My saltwater tank only has two clownfish and starry blenny and a serpent starfish and a emerald crab and some hermit crabs and a porcelain crab. And in it I do a %20 weekly water change. And have a x20 filtration . I did not know that you are suppose to add aragonite in occasionally. How much and how often?

[RTR]

As I said in the original response, about a 1/4" layer every six months to a year plus. You cannot guestimate any closer than that, as the bioload and tank handling vary too much from one operator to the next. You have to play by ear. If the tank pH is slipping, it is time to add aragonite.

[Miller535]

Thank you very much. You have been very helpful

[RTR]

Good luck with extra sand. It is not instantaneous in dissolving, but should bring up the alkalinity slowly and hols it more stable in the future.

If you have a hardness liquid test kit, you can monitor this directly. Compare the tank water pre-change with freshly mixed SW or BW at your chosen density/specific gravity/salinity. The tank will normally be a bity lower, but if the gap widens over time you need to boost it with fresh aragonite. This is far safer and more effective the commercial buffers

Edited to add monitoring.

[Annaxox]

Oh wow! I didn't know that I would have to replace the aragonite, this has helped a lot. ^^

[RTR]

You do not need a deep bed. I normally use only ~ 1/2-3/4" substrate.

If you opt for a DSB, it will be years before any supplemental aragonite needs to be added. But I am too greedy for water volume to "waste" the space - it is not really wasted, I just hate cutting water volume that much. DSB or plenums I like to have in a sump, not in the display tank. But I am a nut for water volume, and FOWLR eats water volme.

[Miller535]

I agree that space is very valuable in a tank. With that said, as time goes on, do you ever remove any old sand before you put new sand in. If I add 1/4 inch every 6 months. In two years I'll have added a inch of sand. Which I dont want to do. I personally don't like very deep sand beds because then it becomes more problematic getting things to keep it sifted.

[Annaxox]

What does DSB stand for?

[Pufferpunk]

http://www.ronshimek.com/deep_sand_beds.html

[Miller535]

Deep sand bed

[RTR]

You are not adding cumulatively - you are replacing what has dissolved. The sand you put in at one grain size will have moved down to sugar sand grain size. The aim is not to lose the original as sufficient exposed grain total surface area available for solution.

If you have ever worked with a CO2 reactor for supplementing Ca, Mg, HCO3 and CO3 - they lose mass fast, as do the depths of DSBs due to the local acidity. That localized acidity really dissolves calcareous sands rapidly. Passive substrate solution is significantly slower but generally adequate. I frequently use OE-RFUG (over-engineered reverse flow under-gravel) to maximize solution rates. If the system water volume is sufficient, it should not be essential to use OE-RFUG, but I like a bit of overkill - even in the long term F-8 study, the alkalinity was rock-steady. But the actual water volume per F-8 was >15 gallons. If someone set a 29 or 30 w/LR and a GSP, the actual water volume will likely be less than 15 gallons - woefully inadequate IMHO. I doubt that even a 55 would have 30 gallons of moving water under such conditions. Which is why I use so many sumps. Nominal volumes are meaningless. Fish live in actual volumes. I can measure those.

If I had to use a single tank for everything, I would house one GSP in a 75 as FOWLR plus a HOB skimmer and a largish HOB 24/7 lighted macroalgae refugium. Then I could be sure of having at least 30 gallons of circulating water volume for the fish and preferably more, Personally I had rather have the fish in a four-foot tank (40-long at least), and a sump (30 or 40-long) for the majority of the LR and the skimmer, with the refugium HOB of the display, with a passive return to the display to deliver maximum live 'pods to the fish.

I just do not believe in stunting fish. I know I did too much of that when I was young. Now that I am old and crabby, if I cannot do it what I consider to be right, I will not do it at all.

HTH