I've no idea and can only pass on information they gave me.
I don't know if this is for all products or not but certainly Exit and 2000 when I was last given information - I'm aware this thread is about Gastropex but assume there are similarities in restrictions and told some products do not contain the same ingredients.
I was told that ingredients are on the box and in the leaflet - I'll have to check (if I have some in English!)
They've given me quite a lot of information but with regard to ingredients and restrictions I got told quite a few things when enquiring after a box with German only information was delivered to me but to start they told me in January 2019 "They are not allowed to be sold in the UK. For starters because there is no English on the box and inside.
All English boxes say that they are appoved by the VMD. If it is not on the box, it is not allowed to be sold there.
If you have the instructions in German, the product is not suitable for the UK because the ingredients are different in these countries due to legal issues.
eSHa 2000 contains in the UK: Ethacridine lactate, Copper Sulphate and Proflavine Hemisulphate.
EXIT contains in the UK: Ethacridine lactate, Malachite green oxalate and Methylene blue.
Some products do not contain the same ingredients."
They told me lots of other things, here's just a few of those things which is maybe worth a flick through but not really read through to see if you need my questions for it to make sense!
Maybe something people don't acknowledge is stopping the use/removing a dechlorinator (e.g. Prime), stopping fertilisation, stopping CO2 - I think that's all in the info below which are just things they've told me, don't shoot the messenger!
"Dear Andrew, Thank you for your interest in our products! You can use eSHa 2000 and eSHa EXIT at the same time. eSHa 2000 contains a little bit of copper and although we do not have any negative results with shrimps (even in overdose), we have heard that shrimps can not tollerate a lot of copper. Since we only use a bit, we do not think that it will be a problem. Please read the leaflets of both products very carefully before use and follow all instructions. (do not use waterconditioner, water parameters must be fine before use, siphon the gravel if you have used waterconditioners etc.) Please dose at a time where you can check your aquarium regularly and perform a waterchange if you think something is wrong. EXIT does not contain copper and is safe for shrimps if instructions are followed. After treatment you can use eSHa Optima to speed up recovery"
"Dear Andrew, Thank you for contacting us about our products! Gastropex and eSHa 2000 contain both coppersulphate so we would not recommend to use both products at the same time. Because they both contain copper we always advise people to be carefull with shrimps, although we do not have any negative results with shrimps (even in overdose), we have heard that shrimps can not tollerate a lot of copper. Some shrimp can handle it perfectly but some sensitive shrimp are not okay with copper. Since we only use a bit, we do not think that it will be a problem. Please read the leaflets of both products very carefully before use and follow all instructions. (do not use waterconditioner, water parameters must be fine before use, siphon the gravel if you have used waterconditioners etc.). So always be carefull when there are shrimps in the aquarium. Dose at a time where you can check the aquarium regularly and keep fresh active carbon nearby to filter over when you think something is wrong and perform waterchanges. eSHa 2000 can be used with EXIT. Kind regards, Nikki Boumans eSHa Labs
ps: Freshwater Summary:
eSHa 2000 + eSHa EXIT = okay
eSHa 2000 + eSHa gdex = okay
eSHa 2000 + eSHa EXIT + eSHa gdex = only if your fish actually have white spot and flukes at the same time.
eSHa EXIT + eSHa gdex = okay.
eSHa HEXAMITA + eSHa EXIT = okay.
eSHa HEXAMITA + eSHa gdex = okay.
eSHa HEXAMITA + eSHa EXIT + eSHa gdex = only if your fish actually have white spot, flagellates and flukes at the same time.
eSHa HEXAMITA + eSHa 2000 = NOT okay. Gastropex and Protalon-707 are NOT okay to combine with products.
Don't use any other products with medicines. So no seachem, sera, tetra, jbl, waterlife, and all the other brands. No plantfertilizers, no CO2, no UV, etc."
"All these kind of products can react with medicines (not just ours but all of them). They can take the medicines out of the water but they can also react with the products and this is not good.
If you have used other products such as conditioner, you have to remove this first before starting the cure. If you are using the waterconditioner to remove chlorine: you can dechlorinate the tap water by running the tap water direct over fresh active carbon before adding is into the tank or you can aerate it by tapping the water through a shower head (hot) and let it stand to cool down before adding it into the tank. Do not fill up your tank with tap water that contains chlorine. If you use waterconditioners or other products we also advise to clean the bottom layer of the tank by siphoning or vacuuming and clean the decorations as waterconditioners sometimes sticks to the bottom and deco like a layer of dust and keeps working. Waterconditioners can cause a reaction when adding other products such as a medicine. Change 50% of the water without the waterconditioners. The waterconditioner left in the other 50% of the water still works. The next day you again change 50% and clean the bottom and decorations. Use the shower head method or the fresh carbon (is the quickest an easiest way) method. Prepare your filter unit by taking out all chemical active filter media (remove carbon, resins etc.). Do not use chemical active filter such as activated carbon, UV, oxidisers, resins etc. You can filter over filter wool, sand and gravel. Keep the filter running day and night. Now your tankwater is safe for starting the treatment. Our medicines are biodegradable and also work for longer than the 3 days you dose. So without a need, do not do a water change and do not filter over active carbon, right after the treatment. The products will keep on working for 2 to 3 days and need to do this for best performance.
We say they CAN react, not that it always does this. For example I believe Seachem Prime says "removes heavy metals from the tapwater" so if you put a medicine in it that contains copper (which is a heavy metal) the prime can remove this part of the medicine. That does not mean that the product can not work because there are other ingredients in there as well that can still do the job."