Second hand tank issues

[Robinski]

I just bought a second hand tank.
It had a baby black and white clownfish and a blue spot puffer, a pile of live rock and a scattering of sand.

It is an aquaone minireef 120 (30g).
I put the rock in a box (no water) and transported all the water back in containers. I kept the existing sand in the bottom and added the same amount of new sand (didn't rinse, cloudiness cleared in 30mins).

I plan to grab natural salt water as I live near the sea and there is a jetty nearby that people collect water from.

Skimmer was absolutely filthy. Centre tube I thought was black till I cleaned it.

Got some test kits and found the following.
Temp 25c
KH 7
Salinity 1.045
pH 8.2
Ammonia 0
Nitrate 0
Rock had a bit of gree algae

My LFS has not had stock for 3 months due to covid and when I went in the day after collecting the tank they had stock but it was a frenzy of buyers. I know I shouldn't have but thinking the tank would have already cycled and the frenzy, I bought a Lawnmower blenny, melanurus wrasse, and standard baby clownfish. I also grabbed one of each of trochus, conch and nassarius snails. I also grabbed a red indica starfish.

Starfish got exposed to air on transfer to the tank and then grabbed hold of a rock and slowly dropped off dead over 2 days.

Live rock has been oozing goo and turning white in places.

Ammonia has risen to 0.125 over 4 days, no Nitrate. Skimmer, after a good clean and calibration is starting to work after 2 days but I am running wet and it is quite white foam.

I pulled the 100w heater out and put a 150w one I had from a freshwater tank a few yrs ago. (Last owner said the heater wasn't big enough and It got cold at night (20c)).

I am finding that the tank is evaporating around 2-3L (1g) of water over 24hrs. Topping up with de-cl tap water (as this reads 0 in salinity reading, others say we have very good pure tap water so don't bother with RO...people bottle it and sell it all over the world as "pure Tasmania"). My tap water has a pH of 7 so buttering with Sodium Bicarb from my swimming pool supply to 8.2 before adding.

Bit worried about the salinity so been taking the odd litre of water out of the tank and replacing with de-cl tap. Doing this slowly and got salinity down to 1.04.

As totally new to marine, any tips or tricks from where I am starting?

 

[Robinski]

 

[helmsreef]

You should be around 1.025 in salinity and when gauging the quality of your tap you want to look at the TDS reading more than the salinity of the tap water.

 

[littlefishy]

That is a gorgeous rock
The above poster is right, "pure" mountain water is high in tds and great for coffee, tea, etc.
R.O. is tastless at 0 tds.
You will be raising your tds every water change.

 

[littlefishy]

In other words, salt and minerals (tds) are left behind on evaporation, so you want to replace evap with 0 tds water to maintain salinity and mineral balance. Distilled water is also 0 tds if you can't get an R.O. system now.

 

[Thomas Jedlicka]

I dont know if this will help but i find it quite shocking you are losing that much water. I would consider a potential slow leak. even my 300+ gallon systems don’t evaporate at that rate

 

[ihavecrabs]

Your starfish likely died from low salinity. You need to get that up to 1.024 ata minimum

 

[Robinski]

I dont know if this will help but i find it quite shocking you are losing that much water. I would consider a potential slow leak. even my 300+ gallon systems don’t evaporate at that rate

I have had a look around the tank and the sump. There is no apparent leak or build up of salt.

The air is really dry in the house. We heat the house quite a bit and heating the cold outside air dries it out at this time of year. My kids all have very dry skin through winter too. Australian houses are not well insulated and are draughty so lots of air turn over too. Spring is almost here so I hope that helps.

 

[Robinski]

Your starfish likely died from low salinity. You need to get that up to 1.024 ata minimum

Do you mean too high. 1.045 is what it was when I got it and I have moved it down to 1.040.

 

[Robinski]

That is a gorgeous rock

What makes you say that?
I ask as I am nervous of the witening of the coraline algae since getting it 5 days ago.

 

[Robinski]

Distilled water is also 0 tds if you can't get an R.O. system now.

I can only find demineralised, will that do?

 

[Robinski]

That is a gorgeous rock
The above poster is right, "pure" mountain water is high in tds and great for coffee, tea, etc.
R.O. is tastless at 0 tds.
You will be raising your tds every water change.

Ignoring the evap issue....if I do a water change with Nat sea water it would make things better as salinity & TDS lower in NSW than tank. I would still have the evap issue though. Right?

 

[ihavecrabs]

Do you mean too high. 1.045 is what it was when I got it and I have moved it down to 1.040.

Ah yes, I read that incredibly wrong! 1.023-1.026 is a better range to shoot for if keeping anything other than just fish.

Also, I wouldn’t trust a plastic hydrometer. What are you using to test salinity?

 

[Uncle99]

Do you mean too high. 1.045 is what it was when I got it and I have moved it down to 1.040.

Why not reduce to 1.025 or if no corals, 1.023?
1.040 is not a good number.

 

[ihavecrabs]

Ignoring the evap issue....if I do a water change with Nat sea water it would make things better as salinity & TDS lower in NSW than tank. I would still have the evap issue though. Right?

Yeah, you can do water changes with natural ocean water, but I’d test the salinity first and adjust as needed

Only replace evaporation with low/0 TDS water.

 

[Robinski]

Thanks for the help so far. Feel like a total newbie. Thought I could pick this up quickly being a water engineer (hydraulic and strategy rather than process).

I have actually got a waterbox on order but it is 3 mths away and I saw this cheap tank so thought it would give me a chance to learn before I approach the big premium set-up. Being responsible for the fish living is giving me more anxiety than I thought.

 

[ihavecrabs]

Thanks for the help so far. Feel like a total newbie. Thought I could pick this up quickly being a water engineer (hydraulic and strategy rather than process).

I have actually got a waterbox on order but it is 3 mths away and I saw this cheap tank so thought it would give me a chance to learn before I approach the big premium set-up. Being responsible for the fish living is giving me more anxiety than I thought.

just wait until you get hooked on coral.. then it’s alkalinity, calcium, magnesium, phosphate, nitrate, and more!
It is a fun challenge though!

 

[Uncle99]

1.040 salinity will be stressful on your fish.

 

[Robinski]

Also, I wouldn’t trust a plastic hydrometer. What are you using to test salinity?

Using a Serenity refractometer. Calibrated to demineralised water, then checked tap (which also read 1.000).
Thought I was good to go, but doubting myself now. 1.045 seems extremely high. Kinda makes sense given the high evap I am getting (and the fact the previous owner didn't mention topping up for evap at all, and I brought his water home with me)

 

[Thomas Jedlicka]

I have had a look around the tank and the sump. There is no apparent leak or build up of salt.

The air is really dry in the house. We heat the house quite a bit and heating the cold outside air dries it out at this time of year. My kids all have very dry skin through winter too. Australian houses are not well insulated and are draughty so lots of air turn over too. Spring is almost here so I hope that helps.

Well that would make more sense and explains that. Also what does the water you are taking read regarding salinity?