If you have completed advanced Kourend Kebos diary achievements You are able to swap the stone boots you have with any other pair of boots that give an attack range bonus. Pegasian boots is the best alternative that will cost around 36M OSRS gold gold.

If you're in a position to pay this bow could be a handful tool to increase the damage of Hydra. But, this bow could cost more than 1.1B at current prices and will not increase your kills per hour by 2 kills. (according to PVMER Woox)

How to reach there:

You can find Alchemical Hydra in Karuulm slayer dungeon. The dungeon is located on Karuulm mountain that is accessible through Rada's blessing Teleport (after finishing the an extremely difficult Kourend Kebos diary), fairies rings (teleport codes C*I*R) that take you just south of Karuulm Mountain, or a skills necklace which will get you closer to Farming guild. The various ways to travel are displayed below:

Once you have reached the dungeon, which is located in the center of Karuulm mountain, you should be following a trail through regular Hydras, just like displayed below:

Alchemical Hydra strategy:

Hydra's basic mechanics includes 2 attack styles , which are either range or magic. Both styles look similar, but magic attack looks more like a form of smoke or cloud, while ranged attack comes with sharp heads and looks in the shape of an edge. The two styles are displayed below:

After you enter the scenario The attacker will target you using one of the styles three times in row. After that, she will change to the next attack style. The prayer must be flipped to activate protections according to her attacks! In the example above, if being in the arena, she'll be able to strike you with a mage attack and you want to protect yourself from mage, and after three attacks switch to ranged security and it goes on. Because of this technique, many PVM'ers joke that counting 3 is the main ability needed to kill Hydra since once you will get used to other mechanics, killing Hydra will be as easy as counting to 3. But there are other things you need to know.

Hydra comes in four different forms , each with its own unique abilities however, these forms are easy to predict and easy to defeat. In the beginning, Hydra will always come in green.

You need to lure her into a red chemical pool , which will weaken her defenses against chemicals. Always begin each instance with a run to Eastern wall, this should position you for easy first quarter of killing:

Green Hydra's main attack is a poison spit. Avoid walking on any squares with poison:

She will utilize her special attack after 3 basic attacks, then she continues attacking with standard attacks for another 9 hits before using her special attack a second time. For instance, she hits you with magical attack 3 times. She will then make use of her special skill to hit you with ranged, and after that she will be attacking you with ranged.

Very important! This attack rotation is common to every Hydra form!

After you will lower her hit points to 75%, she will transform to blue. For this stage, simply walk to the northern wall and lure her into a green chemical pool. It will decrease her chemical defenses:

After her first 3 hits, she'll activate her special capability, which can be described as lightning storm, however this storm isn't anything terrifying. Just run the north-east corner, as shown below:

This will protect you from just one out of two lightning strikes, which can be easily absorbed. Be sure to keep your count to three! Don't try to take in basic attacks and lightning attack at the same time unless you're feeling the same way as Leroooy Jenkins right now. After you've brought Blue Hydra up to 50% HP she will change to her red appearance. You can move your character towards the western wall , and lure her into blue chemical pools, which will lower her defenses:

After her first three attacks she will start walking away from the cheap RS gold and utilize her special attack that could be described as an enchanted maze.