Concentration of dissolved solids

[GaspingGurami]

I've a 1ft cube that has ADA amazonia soil, some seiryu rock and carpeted with hairgrass, HC and Crypt parva. It is fan cooled, non CO2.

Evaporation is around 1L daily, topped up with tap water treated with Nutrafin Aqua Plus. Tap water is around 1dkH, 5dgH.

After 2 months plus of topping up water, I noticed white deposits left behind from evaporation. pH was 7.2-7.4, 4dkH, 8dgH.

Since I don't add any sodium bicarbonate nor any ca or mg, I figure the deposits must be the leftover salts from tap water getting more and more concentated. (weekly, I fertilise 2ml LGA and 1ppm PO4)

Other than using rainwater, distilled or RO water for my top ups, I'm writing to see what you who have similar setups use for topups with your nano tanks.

Would the rising concentration need to be diluted in a certain way? I'm trying to avoid doing water changes as this tank is in my office and I wouldn't want to use too much company's water.

Thanks in advance for sharing your own experience.

[bclee]

The good thing is that the TDS (total dissolved solids) of the water from out tap is relatively low. Therefore, the accumulation is quite tolerable for plants and fishes for some time.

At some point of time you will still probably need to do a water change.

BC

[celticfish]

if your office has AC then turn on the fan only over the weekend. the daily daytime AC should give you a good temp range.

what i do weekly is take 50% out and add back 150% of water. not tank volume. for example, if i take out a litre i'll replace with three litres.

at your rate of evaporation the mineral buildup is hard to aviod.

[GaspingGurami]

BC, Thanks for your reply.

I do not have a TDS meter. Is it possible to gauge TDS buildup by measuring GH? ie, if GH rises above 10 degrees, then it's time to change 50% water.

My concern about allowing the tank to get accostomed to the high TDS is that I'd wipe out the tank after one waterchange from osmotic shock.

I'm surprised that within a short 2 month period, the tank's hardness could have risen 3 degrees and pH value has changed to alkaline despite my having used ADA aqua soil.

I'm thinking perhaps I can soak my top-up water in peat to soften it before adding it to the tank. I have no experience using peat so do you think this method is feasible, or are there any sustainable and simple water softening methods to make 1-2 litres of water a day in the office?

Celticfish, I'm trying to stay clear from waterchanges so that the gossiping tongues in the office don't have to work overtime. Evaporation is high despite the AC because the room temp is high (AC not cold) but RH is low.

[juggler]

Lawrence, do you have coral chips in there? Since your pH is more than 7.

I have two low-tech tanks in the office. One as long as 1.5 yrs without water change. They have coral chips or sea shells in there as well. But I only see a faint layer of white deposits as the water dries up -- more like normal water marks. Is your's scaly and hard to rub off?

I am using peat moss as substrate in those tanks. Have not check the water parameters though.

[GaspingGurami]

Hi KF,

I've got ADA amazonia soil and power sand. There's no coral nor seashells. I've dripped vinegar on the seiryu rock to confirm that it's inert, so I can see no in-tank article that can introduce hardness into the water. Except through the tap water I use for top-up, and the weekly miniscule dose (2ml) of LGA. Does Excel cause hardness?

The white deposits are not like the evaporative salt marks I see in my other tanks, but these are scaly, white, and can be removed only by scratching with finger nails or something hard and sharp.

I'm hoping to bring the pH down too (without adding CO2) as the B. brigittae in this tank are all rather pale, compared to the bright reds I get from those residing in my other low pH tanks.

Could the high pH be due to the new substrate, because there is still insufficient mulm to turn it sour? This is my first time using ADA aquasoil, and my impression from the comments of others are opposite to my observations for this tank.

I've bought a box of Ocean Free black peat granules. I'll soak them in treated water for a night and use this water for top up. Hopefully, this will remove the kH and gH from my top up water and prevent pH from climbing further.

Any thoughts, cautions?

Thanks.

[GaspingGurami]

Here's an update.

The peat tints the water a nice golden brown, IMO it looks better than ketapang's reddish brown stain.

However I think the sudden introduction of low pH from topping-up the water must have shocked the livestock. Shrimps are dying and the choc gourami is not well.

On hindsight, I think it might be better to put the peat in the filter to slowly leach into the aquarium than the sudden change I made.